Re: SSTC does 10 foot sparks - Tesla List Discussion
Edited/Updated: October 21, 2004
Subject: SSTC does 10 foot sparks. Date: Thu, 17 Jun 2004 08:46:10 -0600
Original poster: "Steven Ward"
<srward16-at-hotmail-dot-com>
Coilers,
Recently there has been a lot of advancements in the SSTC area of coiling.
I'm proud to be the first (or at least i *think* im the first) to achieve 10
foot (or better) sparks from a solid state tesla coil! The design is
similar to that of my first ISSTC but using more robust gate drivers and
switching devices, and of course MUCH larger coils.
I will eventually get the details up on my site, but for now here are some
pictures:
http://www.hot-streamer-dot-com/srward16/ISSTCII/ISSTCII_goodpics/
In some of the pics you will see it arcing to a green chair in the foreground,
this is 115"... a few times it struck out beyond that at (i approximate) 125".
And i havent even put the max voltage on it! Im
limited by the ground being so close ;) The coil stands 5" taller than
myself at 6'11". The output is fierce and constantly power arcs to objects
in the 9 foot range with some scattered action at 10+'... im sure if i set it up
just right i can get about 12 feet from this monster and that is my goal (it was
9 feet but that was effortlessly achieved).
Enjoy! All comments welcome. Steve Ward.
Subject: Re: SSTC does 10 foot sparks. Date: Thu, 17 Jun 2004 17:08:02 -0600
Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz>
Hi Steve, Congratulations on a fine achievement. I love the red and green LEDs
showing at the coil base. It looks like something out of a terminator movie.
Have you measured its power consumption yet? Malcolm.
Subject: Re: SSTC does 10 foot sparks. Date: Fri, 18 Jun 2004 12:52:28 -0600
Original poster: "Steven Ward"
<srward16-at-hotmail-dot-com>
Oops, forgot to mention the power consumption is less than 4800W... not exactly
sure because i dont have a watt meter that big but i have it both fused and
breakered to 20A and even after quite long runs it has never popped the fuses or
breakers. My guess is around 4kw to make 10 foot
sparks. Solid State is the only way i would ever have a coil this large at
my house... i cant really feed a pig on my 20A line.
Anyway, i ran the coil again last night for a pretty long time. We had a
"cage of death" set up so i limited my output to 7 feet (though it hit the
ground at 9 feet several times as well). At this distance there aren't
streamers... just power arcs to the cage the whole time. The friends all
loved it and we had a fun safe night that went without problems ;). Steve
Ward.
Subject: Re: SSTC does 10 foot sparks. Date: Fri, 18 Jun 2004 14:47:29 -0600
Original poster: "David Rieben" <drieben-at-midsouth.rr-dot-com>
Steve,
This is a very impressive power vs spark length ratio! I may have to
consider giving up on the pig coils and try to build one of these SSTC
coils to get that kind of performance. I fear that I, like some of the others
have mentioned, am too unfamiliar w/ solid state electronics to comfortably take
on building a SSCT of this magnitude. I know that IGBT's of this magnitude don't
come cheap if you fry one or two of them in the learning process :^O
BTW, are these 10 ft streamers as loud as equivalent 10 ft streamers from a pig
driven coil pulling around 7 to 8 kVA? I figure that they probably aren't just
because the absence of a SG if for no other reason. David Rieben.
Subject: Re: SSTC does 10 foot sparks. Date: Fri, 18 Jun 2004 17:34:45 -0600
Original poster: "John Couture" <johncouture-at-bellsouth-dot-net>
Steve -
Congratulations on your getting 10 foot output sparks from your SSTC coil with
4800 watts input. Do you know that the power output of your Tesla coil can be
much greater than the power input? In other words the output power of your TC
can be much greater than the input of 4800 watts. This means the power
efficiencies (power output/power input) of your TC can be well over 100
percent. It is very difficult if not impossible to determine the true power
input or power output for a particular output spark. The ratio of power output
to power input is mostly an unknown for TC's. To my knowledge no coiler has ever
properly made these measurements.
This is why it makes more engineering sense to use energy input and
energy output in rating TC's. The energy efficiency is then equal to energy
output/energy input. This efficiency is always less than one or 100 percent and
can be measured as I have shown in the past.
As a final comment and to avoid muddying the waters I believe the statement
"4800 watts input for a 10 foot spark" is an acceptable wording for rating TC's
in a free speech country. The pictures of those sparks show that no matter what
you call them they represent a great achievement in Tesla coil progress for
SSTC's. John Couture.
Subject: Re: SSTC does 10 foot sparks. Date: Fri, 18 Jun 2004 21:41:57 -0600
Original poster: "Jim Mitchell"
I think you misunderstood. Steve said the power in was UNDER 4800w because
his 20A fuse never blew. I don't know how it can be possible to make
energy, so his power output is probably less then the input ;0) Though
ISSTC's are pretty efficient. The pulsed powers in the primary are around
300kW I believe, but that is not the continuous average power.
Regards - Jim Mitchell.
Subject: Re: SSTC does 10 foot sparks. Date: Fri, 18 Jun 2004 21:42:16 -0600
Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
Hi John,
What you say may be true, but it is misleading. You can NOT get more
average power out than what is coming in. If you could, you should get a
patent and become rich. Peak power yes. You store up energy over a
large
time and then discharge it in a small time and the peak power out will be
larger than the peak power in.
Gerry R.
Date : Sun, 20
Jun 2004 12:42:57 -0600
Original poster: "John Couture"
<johncouture@bellsouth.net>
Jim - I don't think it is a matter of misunderstanding. However, it is a matter
of understanding the difference between power and energy. Coilers have struggled
with these two words for many years. If with Steve's coil the input is under
4800 watts you have the same problems when using power units for rating Tesla
coils. That is why it is better to use energy when rating Tesla coils. Refer to
my reply to Gerry.
The output power of Steve's coil as you say is very high 300KW. The ISSTC may be
very power efficient. In fact if the 4800 watts input and 300KW output
of Steve's TC are correct the power efficiency is
Power efficiency = output power / input power
= 300 000 / 4800
= 62.5
Tesla coils can have much greater power efficiencies than this. It is less
confusing to call this power gain. Use efficiency only with energy. Note that
energy is not involved when using power units so your "making energy" is not a
problem. John Couture.
-----------
Sent: Friday, June 18, 2004 10:41 PM.
Subject: Re: SSTC does 10 foot sparks
Original poster: "Jim Mitchell"
<Electrontube@sbcglobal.net>
>
I think you misunderstood. Steve said the power in was UNDER 4800w because his
20A fuse never blew. I don't know how it can be possible to make energy, so his
power output is probably less then the input ;0) Though ISSTC’s are pretty
efficient. The pulsed powers in the primary are around 300kW I believe, but
that is not the continuous average power.
>
> Sent: Friday, June 18, 2004 7:34 PM
> Subject: Re: SSTC does 10 foot sparks
>
> > Original poster: "John Couture"
<johncouture@bellsouth.net>
> >
> > Steve -
Congratulations on your getting 10 foot output sparks from your SSTC coil with
4800 watts input. Do you know that the power output of your Tesla coil can be
much greater than the power input?
(Editors note:
Hmm?)
In other words the output power of your TC can be much greater than the input of
4800 watts. This means the power efficiencies (power output/power input) of your
TC can be well over 100 percent. It is very difficult if not impossible to
determine the true power input or power output for a particular output spark.
The ratio of power output to power input is mostly an unknown for TC's. To my
knowledge no coiler has ever properly made these measurements. This is why it
makes more engineering sense to use energy input and energy output in rating
TC's. The energy efficiency is then equal to energy output/energy input. This
efficiency is always less than one or 100 percent and can be measured as I have
shown in the past. As a final comment and to avoid muddying the waters I
believe the statement "4800 watts input for a 10 foot spark" is an acceptable
wording for rating TC's in a free speech country. The pictures of those sparks
show that no matter what you call them they represent a great achievement in
Tesla coil progress for SSTC's. John Couture.
Date : Sun, 20 Jun 2004 17:03:02 -0600
Original
poster: Sean Taylor
<sstaylor@uiuc.edu>
John, I'm sure there will be many people replying to this, so I'll keep it as
short as possible :-)
>I agree you cannot "get more average power out than what is coming in".
However, it is very possible to get much more pulse power out than average
power in.
I completely agree, this is the whole thing with capacitor discharges, you can
charge them at a low rate, and discharge much faster to create high peak
currents. This concept is used all over the place in technology.
With Steve's TC it appears that the average power in is about 4800 watts and the
pulse power out is about 300 KW giving a power gain of 62.5 .
The concept of "power gain" is a VERY misleading one. Power is DEFINED as
energy transfer per unit time, so by definition when comparing two powers,
unless otherwise stated, you are comparing a total power transfer. The
difference is when you consider peak power, which is the instantaneous RATE of
energy transfer.
>With a potential power output of 300 KW it is obvious that a very long spark
would be possible depending on the TC design. That is why using power instead of
energy units is not good for rating Tesla coils. It can exaggerate the output
possibilities of a coil so you have to be very specific about the input
conditions.. If you use energy units you will not have this type of problem. The
energy output units will always be less than the input units.
Not necessarily true. Energy output at a chosen time (perhaps between bangs)
will be much less, about 0, than the input energy. Also, saying input or output
energy entails energy transfer, implying a rate, not just a quantity of
energy. With any sort of energy storage device, energy in and out can be very
different from each other.
>"Peak power out will be larger than peak power in" is another example of the
confusion caused by using power with Tesla coils.
I wouldn't call this a confusion so much as a difference of measurement
techniques.
"Peak power out" cannot be larger than "peak power in" unless there is a time
difference between the two stated powers.
Peak power out and peak power in can be very different, and either one can be
greater than the other. I think what you mean by "unless there is a time
difference", is that the total time that the power is measured over is different
for the input and output. You can have a single spike of power at say 10W, and
measure for however long you want, and still only have a 10W peak, the time
doesn't matter. I think you are confusing integrating over the two times
(yielding energy) rather than recording the peak power transfer.
This means bringing in time into the process which gets you into an energy
process.
Not really, depending on how you use the time. Dividing by time will give an
average power transferred per time, multiplying/integrating will give you an
amount of energy transferred.
It would be preferable to say that "Peak power out will be larger than average
power in". This still requires more
explanation. The time period involved in the output vs the time period involved
in the input. And we are back again into energy out vs. energy in.
A peak power is an instantaneous event and there is no measurement over time for
the peak. It happens, and it's over with, there is no amount of time that
matters. The time that energy is being transferred overall may be (and will be)
different between the input and output, but this is not a concern for peak power
measurements, and is the whole essence of power storage devices/pulse
discharges. It's why a TC works!
Note that when using average power that you are adding time to the power units
which brings you into the energy unit solution. This has caused great confusion
for coilers in the past. Average power is actually energy because you have to
use time to find the average power.
Again, see above, just because you use time doesn't mean you get energy. There
is a big difference between average power and energy. Average power is
calculated from W/sec, over a specified period of time yielding Watts
again. Energy is just a specific quantity of energy, no time involved
whatsoever.
In other words when you connect a wattmeter to the input of a TC you are
measuring many parameters depending on how you want to use them. For example the
wattmeter gives you at the TC input
>
> 1. wattage
> 2. average wattage
> 3. peak wattage
> 4. instantaneous wattage
> 5. volt amps
> 6. RMS wattage ??
Strictly speaking, wattmeter doesn't give you all these things, it gives you
one: average "wattage", or power. Some, with storage functions, will give you
peak power, but this can be the peak over 1 cycle, or the peak instantaneous
power. In an AC circuit, you have instantaneous power, which is defined as
instantaneous current times instantaneous voltage, but is not very meaningful in
terms of what is actually going on because both I and V are going positive and
negative continuously. This is where average power comes in - the average over
one AC cycle.
Because of non-resistive loads, the power transfer can be going in to or out of
the "load", meaning the instantaneous power is positive sometimes, negative
other times, so an average "power" is used to represent what work is actually
being done - also know as the real power, measured in Watts. The RMS current
and RMS voltage, considered without and phase difference is the "apparent power"
- Volt-Amps, and often most devices are rated to a certain VA because the wire
has to handle a certain amount of current, and it doesn't care if it's in phase
with voltage or not, there is still that amount of current to be passed. The
imaginary power, measured in VA reactive, is just the part of the current that
is purely reactive, imaginary, or 90 degrees out of phase with the voltage that
does absolutely no work whatsoever, and can't because the average power is zero
- half the time energy is flowing into the load, the other half out of the load,
the effective energy transfer is zero, and power is zero.
Correctly using all of these parameters can be very confusing. You can avoid all
of the above confusion by properly using energy units to rate Tesla coils. If
the wattmeter is used as an energy meter you have to do some calcs and you end
up with different numbers compared to using it as a power meter. For example a
100 watt wattmeter will give you 50, 100, 200, etc, watt seconds when used as an
energy meter if the times are 1/2, 1, 2, etc, seconds.
So how is this less confusing than using power? I can run my 1" TC for days on
end and claim that "consumed" more than 30 MJ. Then I'll go run my 15" 10 kVA
pig coil for under an hour, and it'll "consume" the same amount of energy. So
what's the point? I can also tell you that one coil has a bang energy of 2 J,
and another 10 J. If the break rate of the first is 600 bps, and the second is
120 bps, they "consume" the same amount of energy per time, or use the same
power. I can also tell you that the National Ignition Facility at LLNL consumes
over 2 MJ in one shot, much less than one second, while running my small TC will
take over 5.5 hours to process the same amount of energy. So, how do you
propose we use energy to compare TC’s? I'm not seeing how it would work.
There is a much more to comparing power vs. energy and I find that in some of my
past posts I have used the words incorrectly. Coilers are correct when they say
that power and energy can muddy the waters.
I think trying to compare energy and power is utterly useless. I think we can
all agree that when we talk about power input, we are talking about average
power or just a rate of energy transfer into our coils. Steve's less than 4800
W input is the average power going into his coil, and also must leave at the
same rate, whether it be in the form of heat, light, or electricity. However,
instead of entering at a (relatively) constant rate as happens on the 60 Hz line
(since 60 Hz is slow compared to RF), the power is leaving in large pulses that
happen as often as he dictates by the break rate of the coil, and while these
peak powers occur at a lower duty cycle than the input power has, there are much
larger peak powers (maximum of instantaneous power) present on the output.
Okay, so that wasn't as short as I expected, but I hope that clears up some
nomenclature questions for everybody (and maybe for myself, as I'll probably be
corrected on some things I wrote). Sean Taylor, Urbana,
IL
Date : Mon, 21 Jun 2004 08:05:18 -0600
Original
poster: "Steve Conner"
<steve.conner@optosci.com>
>Do you know that the power output of your Tesla coil can be much greater than
the power input?
Oh wow, then I can feed the output back to the input and get a TC that runs for
ever, and powers my house too ::)
Seriously though, John is talking about PEAK power. This is hard to measure
directly, but we can do it by "fitting" a PSpice simulation to give very similar
waveforms, voltages, and currents to what we observe experimentally, and then
asking PSpice to calculate the power for us.
It may not be super accurate, but I estimate it is there to within +/- 15%. I
have done the numbers for a coil design similar to Steve's ISSTC II, and the
peak output power (from H-bridge to primary) is around 250kW, which is certainly
more than the 4.8kW he is putting in. (The OLTC II had 130kW peak output, but
ran out of steam after about 60 microseconds.)
I also estimate that the energy efficiency (as John defined it) of an ISSTC is
considerably greater than 75%. I calculated the OLTC II to be 75% and the ISSTC
is probably somewhat more efficient again, I would say 85%.
The margin of error in these estimates is 10% (i.e., the ISSTC could be anywhere
between 75% and 95% efficient)
Note: The energy efficiency as described by John is the same as (average power
out/average power in)
Steve C.
Date : Tue, 22 Jun 2004 08:29:44 -0600
Original
poster: "John Couture"
<johncouture@bellsouth.net>
John - I have made recommendations in the past for testing Tesla coils when they
are rated in energy rather than power units. These tests leave a lot to be
desired and would be improved by coilers over time if they were used. Some
coilers in the past have already performed these types and found no major
problems in using them. The tests do end up with shorter spark lengths.
John Couture
Original
poster: "John Couture"
<johncouture@bellsouth.net>
Steven - I assume you have read my post to Gerry which mentions peak powers,
etc, etc. You are the first to mention power factors. In Gerry's post I was
referring only to power as wattage at 100 percent power factor. When power
factor is brought into the picture things get even more complicated. If power
factor is involved things are a lot less complicated if energy is used to rate
Tesla coils.
Power is equal to Volts times Amps or VA. If the VA is in watts the power factor
is 100 percent. Normally when only VA is mentioned the power factor is something
less than 100 percent. Of course coilers don't always stick to this convention
which again confuses the TC power rating. Here again there can be confusion
when rating a TC in power. There is less confusion if the TC rating is in energy
as watt seconds or joules.
With Tesla coils the bottom line is
Power output can be greater than power input
Power is in watts, average watts, peak watts, volt amps, etc.
Energy output can not be greater than energy input
Energy is in watt seconds or joules
The power input can be in many forms as I mentioned in my post to Gerry.
The energy input can be in only one form and that is watt seconds (joules).
Power factor is involved with TC power ratings
Power factor is not involved with TC energy ratings. Why??
Power factor is due to reactive components in the TC. These components produce
reactive powers. Energy is not involved with reactive powers. Refer to my post
to Gerry where I show what happens when the wattmeter is used as an energy
meter.
I hope I haven't muddied the waters again. John Couture
----------------------------------------------
Sent: Sunday, June 20, 2004 1:40 PM.
Subject: Re: SSTC does 10 foot sparks
> Original poster: "Steven Ward"
<srward16@hotmail.com>
>
> From what i understood, i thought John was referring to power factor issues
and other things like "average power" where really all the energy may still be
accounted for. But I’m still a bit unclear about what you meant John, maybe you
could elaborate??
>
> IF it is just a question of peak powers, I recall my pspice simulations
suggesting something of around 1.5 megawatts peak from the IGBT’s.
>
> Steve
>
>
> >Subject: Re: SSTC does 10 foot sparks
> >Date: Fri, 18 Jun
2004
21:42:16
-0600
> >
> >Original poster: "Gerry Reynolds"
<gerryreynolds@earthlink.net>
> >
> >
> >Hi John, What you say may be true, but it is misleading. You can NOT get
more average power out than what is coming in. If you could, you should get a
patent and become rich. Peak power yes. You store up energy over a large time
and then discharge it in a small time and the peak power out will be larger than
the peak power in.
Gerry R.
> >
> > > Sent:
Friday, June 18, 2004 1:52 PM
> > > Subject: Re: SSTC does 10 foot sparks
> > > > Original poster: "Steven Ward"
<srward16@hotmail.com>
> > > > Oops, forgot to mention the power consumption is less than 4800W... not
exactly sure because i don’t have a watt meter that big but I have it both fused
and breakered to 20A and even after quite long runs it has never popped the
fuses or breakers. My guess is around 4kw to make 10 foot sparks. Solid
State is the only way i would ever have a coil this large at my house... I cant
really feed a pig on my 20A line.
> > > >
> > > > Anyway, I ran the coil again last night for a pretty long time. We had
a "cage of death" set up so i limited my output to 7 feet (though it hit the
ground at 9 feet several times as well). At this distance there aren’t
streamers... just power arcs to the cage the whole time. The friends all loved
it and we had a fun safe night that went without problems ;). Steve Ward
> > > >
> > > >
>Subject: Re: SSTC does 10 foot sparks
> > > > >Date: Thu, 17 Jun 2004
18:54:02 -0600
> > > > >Original poster: "Brian"
<ka1bbg@webryders.net>
> > > > >Hi, NICE! Do you have any idea what the power input is? You are
"HOT" on these ss coils! Brian f.
> > > > >To:
<tesla@pupman.com>
> > > > >Sent: Thursday, June 17, 2004 10:46 AM
> > > > >Subject: SSTC does 10 foot sparks
> > > > > > Original poster: "Steven Ward"
<srward16@hotmail.com>
> > > > > >
> > > > > > Coilers, Recently there has been a lot of advancements in the SSTC
area of coiling. I’m proud to be the first (or at least i *think* im the
first) to achieve 10 foot (or better) sparks from a solid state tesla coil! The
design is similar to that of my first ISSTC but using more robust gate drivers
and switching devices, and of course MUCH larger coils.
> > > > > >
> > > > > > I will eventually get the details up on my site, but for now here
are some pictures:
> > > > > >
> > > > > >
http://www.hot-streamer.com/srward16/ISSTCII/ISSTCII_goodpics/
> > > > > >
> > > > > > In some of the pics you will see it arcing to a green chair in the
foreground, this is 115"... a few times it struck out beyond that at (I
approximate) 125". And I haven’t even put the max voltage on it! I’m limited
by the ground being so close ;) The coil stands 5" taller than myself at
6'11". The output is fierce and constantly power arcs to objects in the 9 foot
range with some scattered action at 10+'... I’m sure if I set it up just right i
can get about 12 feet from this monster and that is my goal (it was 9 feet but
that was effortlessly achieved). Enjoy! All comments welcome.
Steve Ward
Date : Tue, 22 Jun 2004 08:29:32 -0600
Original
poster: "John Couture"
<johncouture@bellsouth.net>
Sean -
Thank you for your reply. It appears that you are in agreement with what I was
recommending and that is to use energy instead of power to rate your Tesla
coils. You said your TC was 30 MJ which is rating your coil in joules of energy.
I agree with you that to compare energy and power is utterly useless. This is
like comparing apples and oranges. This thread discusses the comparing of Tesla
coils not the comparing of power and energy. I recommend that coilers use
energy instead of power to compare their coils which is what you are doing.
There are many coilers that use their watt meters to measure several TC
parameters. However, I see no problem in your using your wattmeter to measure
only average watts.
Refer to my reply to Steven regarding your mention of imaginary power (power
factor). Steven was commenting on power factors. John Couture
-------------------------------------
Sent: Sunday, June 20, 2004 6:03 PM
Subject: Re: SSTC does 10 foot sparks
> Original poster: Sean Taylor
<sstaylor@uiuc.edu>
>
> John, I'm sure there will be many people replying to this, so I'll keep it as
> short as possible :-)
>
> >I agree you cannot "get more average power out than what is coming in".
However, it is very possible to get much more pulse power out than average
power in.
>
> I completely agree, this is the whole thing with capacitor discharges, you can
charge them at a low rate, and discharge much faster to create high peak
currents. This concept is used all over the place in technology.
>
> With Steve's TC it appears that the average power in is about 4800 watts and
the pulse power out is about 300 KW giving a power gain of 62.5
.
>
> The concept of "power gain" is a VERY misleading one. Power is DEFINED as
energy transfer per unit time, so by definition when comparing two powers,
unless otherwise stated, you are comparing a total power transfer. The
difference is when you consider peak power, which is the instantaneous RATE of
energy transfer.
>
> >With a potential power output of 300 KW it is obvious that a very long spark
would be possible depending on the TC design. That is why using power instead of
energy units is not good for rating Tesla coils. It can exaggerate the output
possibilities of a coil so you have to be very specific about the input
conditions. If you use energy units you will not have this type of problem. The
energy output units will always be less than the input units.
>
> Not necessarily true. Energy output at a chosen time (perhaps between bangs)
will be much less, about 0, than the input energy. Also, saying input or output
energy entails energy transfer, implying a rate, not just a quantity of
energy. With any sort of energy storage device, energy in and out can be very
different from each other.
> "Peak power out will be larger than peak power in" is another example of the
confusion caused by using power with Tesla coils.
>
> I wouldn't call this a confusion so much as a difference of measurement
techniques.
>
> "Peak power out" cannot be larger than "peak power in" unless there is a
time difference between the
> >two stated powers.
>
> Peak power out and peak power in can be very different, and either one can be
greater than the other. I think what you mean by "unless there is a time
difference . . . " is that the total time that the power is measured over is
different for the input and output. You can have a single spike of power at say
10W, and measure for however long you want, and still only have a 10W peak, the
time doesn't matter. I think you are confusing integrating over the two times
(yielding energy) rather than recording the peak power transfer.
>> This means bringing in time into the process which gets you into an energy
process.
>
> Not really, depending on how you use the time. Dividing by time will give an
average power transferred per time, multiplying/integrating will give you an
amount of energy transferred.
>
> It would be preferable to say that "Peak power out will be larger than
average power in". This still requires more explanation. The time period
involved in the output vs. the time period involved in the input. And we are
back again into energy out vs. energy in.
>
> A peak power is an instantaneous event, there is no measurement over time for
the peak. It happens, and it's over with, there is no amount of time that
matters. The time that energy is being transferred overall may be (and will be)
different between the input and output, but this is not a concern for peak power
measurements, and is the whole essence of power storage devices/pulse
discharges. It's why a TC works!
>
>
> >Note that when using average power that you are adding time to the power
units which brings you into the energy unit solution. This has caused great
confusion for coilers in the past. Average power is actually energy because you
have to use time to find the average power.
>
> Again, see above, just because you use time doesn't mean you get energy.
There is a big difference between average power and energy. Average power is
calculated from W/sec, over a specified period of time yielding Watts
again. Energy is just a specific quantity of energy, no time involved
whatsoever.
>
> In other words when you connect a wattmeter to the input of a TC you are
measuring many
parameters depending on how you want to use them. For example the wattmeter
gives you at the TC input
> >
> > 1. wattage
> > 2. average wattage
> > 3. peak wattage
> > 4. instantaneous wattage
> > 5. volt amps
> > 6. RMS wattage ??
>
> Strictly speaking, wattmeter doesn't give you all these things, it gives you
one: average "wattage", or power. Some, with storage functions, will give you
peak power, but this can be the peak over 1 cycle, or the peak instantaneous
power. In an AC circuit, you have instantaneous power, which is defined as
instantaneous current times instantaneous voltage, but is not very meaningful in
terms of what is actually going on because both I and V are going positive and
negative continuously. This is where average power
> comes in - the average over one AC cycle.
>
> Because of non-resistive loads, the power transfer can be going in to or out
of the "load", meaning the instantaneous power is positive sometimes, negative
other times, so an average "power" is used to represent what work is actually
being done - also know as the real power, measured in Watts. The RMS current
and RMS voltage, considered without and phase difference is the "apparent power"
- Volt-Amps, and often most devices are rated to a certain VA because the wire
has to handle a certain amount of current, and it doesn't care if it's in phase
with voltage or not, there is still that amount of current to be passes. The
imaginary power, measured in VA reactive, is just the part of the current that
is purely reactive, imaginary, or 90 degrees out of phase with the voltage that
does absolutely no work whatsoever, and can't because the average power is zero
- half the time energy is flowing into the load, the other half out of the load,
the effective energy transfer is zero, and power is zero.
>
> >Correctly using all of these parameters can be very confusing. You can avoid
all of the above confusion by properly using energy units to rate Tesla coils.
If the wattmeter is used as an energy meter you have to do some calcs and you
end up with different numbers compared to using it as a power meter.
> >For example a 100 watt wattmeter will give you 50, 100, 200, etc, watt
seconds when used as an energy meter if the times are 1/2, 1, 2, etc, seconds.
>
> So how is this less confusing than using power? I can run my 1" TC for days
on end and claim that "consumed" more than 30 MJ. Then I'll go run my 15" 10
kVA pig coil for under an hour, and it'll "consume" the same amount of
energy. So what's the point? I can also tell you that one coil has a bang
energy of 2 J, and another 10 J. If the break rate of the first is 600 bps, and
the second is 120 bps, they "consume" the same amount of energy per time, or use
the same power. I can also tell you that the National Ignition Facility at LLNL
consumes over 2 MJ in one shot, much less than one second, while running my
small TC will take over 5.5 hours to process the same amount of energy. So, how
do you propose we use energy to compare TC’s? I'm not seeing how it would work.
>
>
> >There is a much more to comparing power vs. energy and I find that in some of
my past posts I have used the words incorrectly. Coilers are correct when they
say that power and energy can muddy the waters.
>
> I think trying to compare energy and power is utterly useless. I think we can
all agree that when we talk about power input, we are talking about average
power, or just a rate of energy transfer into our coils. Steve's less than 4800
W input is the average power going into his coil, and also must leave at the
same rate, whether it be in the form of heat, light, or electricity. However,
instead of entering at a (relatively) constant rate as happens on the 60 Hz line
(since 60 Hz is slow compared to RF), the power is leaving in large pulses that
happen as often as he dictates by the break rate of the coil, and while these
peak powers occur at a lower duty cycle than the input power has, there are much
larger peak powers (maximum of instantaneous power) present on the output.
>
> Okay, so that wasn't as short as I expected, but I hope that clears up some
nomenclature questions for everybody (and maybe for myself, as I'll probably be
corrected on some things I wrote).
>
> Sean Taylor, Urbana, IL
Date : Tue, 22 Jun 2004 08:35:08 -0600
Original
poster: "Steven Ward"
<srward16@hotmail.com>
Hmm, Good question, how do we measure the input/output power? I don’t know
myself and wasn’t sure it really even mattered, aside from being reasonably
close and honest with my guesses. Someone wanna seal up a TC in a big styrofoam
container and see how much heat we create? hehehe. Seriously, I can’t myself
afford such measuring equipment other than some cheap ammeters and a small
wattmeter (that is too little for this coil). What I *can* do is use previous
knowledge gained from my first prototype and others work to make good guesses at
things like how much power im using and what efficiency. The other thing i
can rely on is simulation results from pspice.
The way i see it is, i haven't blown the 20A fuse yet and ive had several long
runs so far (telling me it likely isnt pulling more than 20A). Other thing is
that my coil slightly beats Freau's spark length formula... well this makes
perfect sense, no gap losses (and i will tell you, my power components arent
wasting much at all, they run cold to the touch).
So i guess whats most important to me (and likely many others) is that you can
get 11 foot sparks (i hit 11'4" the other night) on a 20A 240V line without
popping breakers and without a pig. Steve
>Subject: Re: SSTC does 10 foot sparks
>Date: Mon, 21 Jun
2004
08:03:02
-0600
>
>Original poster: "john cooper"
<tesla@tesla-coil.com>
>
>Very interesting stuff, how do we agree on a baseline or procedure for energy
in/energy out measurements? Or am I asking too much? I'd be most interested in
someone describing and identifying the equipment/measurement techniques
necessary. John
Date : Tue, 22 Jun 2004 08:33:11 -0600
Original
poster: Sean Taylor
<sstaylor@uiuc.edu>
I don't see why you are stuck on measuring energy in and out. Don't worry about
the energy into a coil, as the power contains all the information needed (well,
not all, but give a good idea of what the coil is consuming). As for output,
the debate continues as to how to compare output. Of course, spark length is
the easiest thing to measure, but a good metric for frequency of strikes is
needed. Also not considered on the output here, directly at least, is the
streamer current. Perhaps those with the capability could measure the peak
current at the base of the secondary for a second parameter for performance, as
well as break rate.
There are many unknowns in the output of a Tesla Coil and can not be easily
measured. However, computer simulations have gotten so good and close to real
life circumstances that we don't really have a choice now but to believe the
results they give us, despite the fact that we can't measure everything and
compare the results. People can claim whatever they want for the output of
their TC, but it seems to be that it's not just a pissing contest, but a
difference in what we see for the potential (no pun intended) for output – i.e,.
max spark length, or straight spark length, etc. It has been discussed several
times how we can standardize measuring output, and there isn't much to do unless
we can get everyone to run there coils at Standard Temp. and Pressure, with
known humidity for a known amount of time and count the number of strikes for a
given length in the known time - not very realistic. As Terry realized a while
ago, his GMIHESLR (did I get that all right?) record was skewed because he's at
a higher elevation in Colorado
than other competing and was able to get a longer spark length because of this.
Sean Taylor, Urbana, IL
Date : Tue, 22 Jun
2004
20:14:13
-0600
Original
poster: "John Couture"
<johncouture@bellsouth.net>
Steve, Thank you for trying to help coilers understand the difference between
energy and power.
Yips! You missed quoted what I said. I did not mean to covey the impression that
I though that power could be somehow made equal to energy. This again shows how
easy it is to confuse energy and power.
You said "Note: The energy efficiency as described by John is the same as
(average power out/average power in"
I actually said "Note that when using average power that you are adding time to
the power units which brings you into the energy unit solution."
I definitely did not mean to convey that average power was energy. Average
power is a power unit. Energy is an energy unit.
Power and energy like apples and oranges are not equal or should they be
compared as equals.
Don't feel bad. This power/energy battle has been going on for a long time on
the List. The problem is still in much of today’s literature. For example I was
just reading about power on the internet and it mentioned power consumption. On
the surface this sounds OK. However, power is like volts or amps and to say
these parameters are consumed doesn't make sense. But energy is a quantity of
electricity and this can be consumed.
Also be careful with how you use PSpice and other simulators. Energy has to do
with efficiency. Efficiency with simulaors can be GIGO.
John Couture
--------------------------------------
Date : Tue,
22 Jun 2004
20:15:04 -0600
Original poster: "john cooper"
<tesla@tesla-coil.com>
Yeah, another good point, does it really matter what the power in/out is as long
as it's impressive? Probably not at this early stage.
But we should all be able to measure input, roughly at least, as long as we
remember to look at the meters, not the discharge. Maybe that with length of
output could be a baseline for those inclined to pay attention to such
things? Who says strip or chart recorders are obsolete? I do have some ideas
for directly measuring the output and if it pans out I'll post it.
Has anyone else seen or used the copper tube 'ladder' that allows you to fire a
huge (or smaller) coil indoors and to get an idea of the output 'power'? Good
for tuning (how many gaps will it jump). Bob Svangren from Washington
state was the first that I know of to make and use one of these and Richard Hull
may have also experimented with them, this was probably over 10 years ago
though. That idea may merit some thought, I've always wanted to construct one.
Hmmmmmmm. John
Date : Tue, 22 Jun
2004
22:38:13
-0500
A copy of
this post was sent to the Tesla List
John - The recommendations are so simple I can list then right here. To test any
electrical device you find the energy input and the energy output. This will
give you the overall efficiency with the equation
Eff = energy out/energy in. Multiply this decimal by 100 and you get the percent
efficiency. If it is an electric motor the input can be measured by a wattmeter
and the output by a Prony brake or dynamometer. The wattmeter will give you
watts per second for the energy input. The Prony brake or dynamometer will give
you a force that can be converted into energy output using the proper equations.
You can do a similar test with Tesla coils by making some adjustments. The
wattmeter will also give you watts per second for the energy input. As you no
doubt know the spark output can be a problem to relate it to an energy output..
Because the input energy is in watt seconds you have to relate the spark output
to the number of sparks per second. Because the input watts are a continuous per
second stream (of energy) the output sparks have to be a continuous equal length
stream (of energy). This type of output is subject to controversy and subject to
change in the future.
I tested a small TC. The input was 120 watts (to get the 1 joule per 8.25 inch
spark). The output was a
continuous number of sparks with equal length of 8.25 inches. The input was from
the 60 HZ utility so the number of sparks were assumed to be 120 per second.
This produced a very interesting number. How do you find the energy in a single
8.25 inch spark under controlled spark conditions? This is the first time that
this unique quantity of energy has ever been determined. The joules of energy
in a single 8.25 inch spark! It was found like this. From the above test the
total energy input per second / total number of sparks = 1 watt second input or
1 joule input per 8.25 inch spark. This test can be easily duplicated with any
small TC. You can then boast to fellow coilers that you found the true energy
in a single 8.25 inch or similar spark.
Of course there is a lot more but this should get you started. John
Couture
Date : Tue, 22 Jun
2004
20:14:35
-0600
Original
poster: FutureT@aol.com
In a message dated 6/22/04
3:52:27 PM Eastern Daylight Time,
tesla@pupman.com writes:
>The way i see it is, i havent blown the 20A fuse yet and ive had several long
runs so far (telling me it likely isnt pulling more than 20A). Other thing is
that my coil slightly beats Freau's spark length formula... well this makes
perfect sense, no gap losses (and i will tell you, my power components arent
wasting much at all, they run cold to the touch).
Steve,
Your SSTC results are truly fantastic and have progressed much faster than I
ever expected. It makes sense that the losses are lower than in a spark gap
TC. A good spark gap TC in the larger sizes can sometimes approach
spark length inches = 2*sqrt input watts
The 1.7* figure that I usually use is a good average figure for efficient coils
but since larger coils tend to be more efficient, they can reach a higher
coefficient figure.
Some 20A breakers can supply somewhat more than 20 amps for awhile.
I point all this out just to fill in the picture a little. John.
>So i guess
what's most important to me (and likely many others) is that you can get 11 foot
sparks (i hit 11'4" the other night) on a 20A 240V line without popping breakers
and without a pig. Steve.
Date : Wed, 23 Jun
2004
11:21:47
-0600
Original poster: "John Couture"
<johncouture@bellsouth.net>
Steven -
How you measure the TC input isn't important. This is a free country and you can
do as you please, within reason. The point that matters is to understand what
you are measuring. If you don't understand what you are measuring you cannot
talk intelligently about your coil. For example, if you are rating your TC in
power units (watts) it does not make engineering sense to say the efficiency is
equal to anything. Efficiency refers to energy units not to power
units. However, if you are rating your TC in power units it does make sense to
say it has a power gain of a certain amount. You can then use this number to
compare with other TC's.
The above, of course, does not solve the problem of how to properly test and
rate a Tesla coil when using spark length as the TC output. In the past only a
few coilers could rate and test their coils properly. This resulted in shorter
sparks. However, everyone was more impressed by that random extra long spark so
any tests that gave shorter sparks were not popular. The problem was the true
input energy that actually created that special extra long spark could not be
determined so true TC comparisons could not be made. Only continuous sparking
with fixed lengths made sense. But it does not appear that we will ever get away
from that mysterious random extra long spark test with an unknown input ( except
maybe for one shot tests). John Couture
Date : Wed, 23 Jun
2004
11:22:36
-0600
Original
poster: humanb@chaoticuniverse.com
I really do not know why this is such a issue:
Power= work (or energy transfer) per unit time:
P = dW / dt
Energy= the theoretical maximum amount of work that can be obtained from a
system: the joule.
The coilers here, for the most part, are not concerned with semantics, just how
long the spark is -vs- when
the breaker trips ;-O But when Steve says he hasn't tripped the 20 amp breaker,
that really doesn't mean
much. The breakers can see much greater than rated current for short periods of
time, and it doesn't
account for the resistance to the coil...
But John, I seem to remember a time when you didn't want the "un-holy" subjects
of VTTC's and SSTC's even discussed on this list ;-) . Regards, David Trimmell.
Date : Wed, 23 Jun 2004 11:21:25 -0600
Original
poster: "Gerry Reynolds"
<gerryreynolds@earthlink.net>
Hi Sean, I've always been a believer in measuring as directly as possible what
it is that we want out of a system and optimize for that. Each one of us may
have a different view in what they want. Example, some want max spark length
for a single bang. Some want max spark length for a demo and doesn't care how
it is done just so it is done which may imply the best trade off between single
bang spark length and spark growth as function of BPS, etc. Some may want many
shorter sparks and some may want fewer longer sparks. It seems like a standard
for comparison is not too meaningful since we all have different tastes. The
important thing is to have fun and get what you want out of your system.
Gerry R.
>Subject: Re: SSTC does 10 foot sparks
>Date: Wed, 23 Jun
2004
11:21:47
-0600
>
>Original poster: "John Couture"
<johncouture@bellsouth.net>
>
>Steven -
>
>How you measure the TC input isn't important. This is a free country and you
can do as you please, within reason. The point that matters is to understand
what you are measuring. If you don't understand what you are measuring you
cannot talk intelligently about your coil.
Well of course you can’t.
For example, if you are
>rating your TC in power units (watts) it does not make engineering sense to say
the efficiency is equal to anything.
I suppose but...
Efficiency refers to energy units
>not to power units.
Here is the issue. The operation of the ISSTC is such that it’s quite difficult
to say just how much energy is in the tank circuit over the period of the
"burst". You see, the tank cap is not so much a storage device as it is in a
normal spark gap coil where you charge the cap to a known voltage (thus you know
its energy in joules) and discharge this energy into the primary coil. With the
ISSTC you are constantly adding little bits of energy on every RF cycle... So,
it is in my opinion that a reasonably accurate method of determining the
"energy" for each "bang" or "burst" is to simply take the input power in Watts
and divide by the number of BPS (burst per second). So for example, if i was
using say 4000W average input power with exactly 100 bps that would be 40j per
burst. I would assume a similar spark output from a SGTC that had a 40j
capacitor and that was of great efficiency (efficiency merely being getting most
of that energy into the spark).
Can we agree on the above paragraph?
If so, lets make things worse ;). Now say i go nuts and run my coil with
1000bps. The input power (assuming 40j per burst) should be about 40kw. Now at
this power the arcs are going to be MUCH longer due to streamer growth
issues. But now if i was to compare the first scenario (at 100bps) vs. the
second (1000bps) to be the same simply because the energy per burst is equal,
then there would be a very large discrepancy here. One coil would be doing 10
foot sparks while the other could spit out some 30 feet of plasma.
However, if you are rating your TC in power units it does make sense to say it
has a power gain of a certain amount. You can then use this number to compare
with other TC's.
I guess so, but i never thought of that method of comparing coils.
>The above, of course, does not solve the problem of how to properly test and
rate a Tesla coil when using spark length as the TC output. In the past only a
few coilers could rate and test their coils properly.
I’m sure it has been covered a dozen times, but could you briefly elaborate on
how the tested and rated "properly"?
This resulted in shorter sparks. However, everyone was more impressed by that
random extra long spark so any tests that gave shorter sparks were not popular.
Yeah, that sounds likely. I like to hit a target distance several times before
i make a fuss about it.
>The problem was the true input energy that actually created that special extra
long spark could not be determined so true TC comparisons could not be made.
I suppose if you had the right tools thats possible... like a storage scope with
infinite recording time and a synched up video camera to see just what happens
when you get the lucky strike ;)
Only continuous sparking with fixed lengths made sense.
Hmmm, im not sure about that. TCs are too random to be judged like that, I
think. Steve .
But it does not appear that we will ever get away from that mysterious random
extra long spark test with an unknown input ( except maybe for one shot tests).
John Couture
Date : Wed,
23 Jun 2004
16:53:53 -0600
> On Tue, 22 Jun
2004
20:14:13
-0600, "Tesla list" wrote:
>
> >
> > Original poster: "John Couture"
> >
<johncouture@bellsouth.net>
> >>>>>>>>>>Snip<<<<<<<<<<<<<<<<<<>
> > Don't feel bad. This power/energy battle has been going on for a long time
on the List. The problem is still in much of today’s literature. For example I
was just reading about power on the internet and it mentioned power
consumption. On the surface this sounds OK. However, power is like volts or
amps and to say these parameters are consumed doesn't make sense. But energy is
a quantity of electricity and this can be consumed.
> >>>>>>>>>>>>Snip<<<<<<<<<<<<<<<<<<<<<<> John Couture
Date : Wed, 23 Jun 2004 16:53:41 -0600
Original
poster: "Eastern Voltage Research Corporation"
<dhmccauley@easternvoltageresearch.com>
I don't agree with that one bit. There are two parameters. RMS input power
(measured at the incoming AC) and spark length. Although it may not be
scientifically correct to measure a tesla coil like this, its about the easiest
way to compare two coils and how efficient one coil is to another.
Coil A puts out 10 foot arcs with only 1kW RMS power measured at the plug.
Coil B puts out 5 foot arcs with the same 1kW RMS power measured at the plug.
For 99.9999 percent of the coilers out there with the exception of yourself who
always insists on making things more complicated than they need be, this
comparison is perfectly okay.
If Steve Ward's solid state tesla coil can put out 10 foot arcs with only 500
watts RMS input power and my coil can only put out 3 foot arcs with the same 500
watts RMS input power, then damn, Steve's got the much better coil. All this
energy stuff just confuses everyone. Keep it simple.
Now if you want to go all the way and make true scientific measurements to
compare two coils, that’s fine too. But for straight out of the bucket
comparisons, this way works just fine for me.
Dan
> If you don't understand what you are measuring you cannot talk intelligently
about your coil. For example, if you are rating your TC in power units (watts)
it does not make engineering sense to say the efficiency is equal to anything.
Efficiency refers to energy units not to power units. However, if you are
rating your TC in power units it does make sense to say it has a power gain of a
certain amount. You can then use this number to compare with other TC's.
>
> The above, of course, does not solve the problem of how to properly test and
rate a Tesla coil when using spark length as the TC output. In the past only a
few coilers could rate and test their coils properly. This resulted in shorter
sparks. However, everyone was more impressed by that random extra long spark so
any tests that gave shorter sparks were not popular. The problem was the true
input energy that actually created that special extra long spark could not be
determined so true TC comparisons could not be made. Only continuous sparking
with fixed lengths made sense. But it does not appear that we will ever get away
from that mysterious random extra long spark test with an unknown input ( except
maybe for one shot tests). John Couture
Date : Wed, 23 Jun
2004
21:22:17
-0600
Original
poster: Sean Taylor
<sstaylor@uiuc.edu>
I've gotta reply to this . . .
On Wed, 23 Jun 2004 11:21:47 -0600, Tesla list
<tesla@pupman.com> wrote: If you are rating your TC in power units (watts)
it does not make engineering sense to say the efficiency is equal to anything.
Efficiency refers to energy units not to power units. However, if you are
rating your TC in power units it does make sense to say it has a power gain of a
certain amount. You can then use this number to compare with other TC's.
Giving an efficiency in power makes perfect sense. Most devices are rated in
this way. A motor has a certain electrical power in, and a certain mechanical
power output. The efficiency is defined as Mechanical power out / electrical
power in. A heater, lightbulb, and many other devices can be given an
efficiency rating the same way! What doesn't make sense is to say we have a
motor which has a certain power output, and then try to calculate the energy
output by lifting a mass, or some other means and at the same time monitoring
the input power and integrating - much more of a pain, and will arrive at
(approximately, due to measurement error) the same result.
>The above, of course, does not solve the problem of how to properly test and
rate a Tesla coil when using spark length as the TC output. In the past only a
few coilers could rate and test their coils properly. This resulted in shorter
sparks. However, everyone was more impressed by that random extra long spark so
any tests that gave shorter sparks were not popular. The problem was the true
input energy that actually created that special extra long spark could not be
determined so true TC comparisons could not be made. Only continuous sparking
with fixed lengths made sense. But it does not appear that we will ever get away
from that mysterious random extra long spark test with an unknown input ( except
maybe for one shot tests). John Couture
What is rating a coil "properly"? The only way to have a relatively constant
bang energy is to use a triggered type of gap (rotary, etc.) and then how do you
calculate the energy in and out? What is rated "properly" such that the coil
ran with a "constant" length spark? As line voltage fluctuates, and
environmental conditions change, so will the spark length on the output, and
there is no "rating" that will change that. I am interested to know what you
are suggesting changing on a coil that would "rate it properly". Do you have
any documented proof that this was done, or what was changed?
In your other post regarding the energy in a single spark, I'm sorry to say, but
that is complete bull. There are several problems with the logic - 1) How was
the breakrate known to be 120? 2) The system definitely isn't lossless!!! 3)
Wattmeters don't give you Watts/sec, just watts, that's it! 4) There is
streamer growth over successive bangs, so unless you know the voltage you
charged the tank gap too, are running in a single shot type of set up, and know
the exact losses of the system, there is no way to know the energy in the 8.25"
arc!! As you state, there IS a lot more, but the problem is this isn't even a
start towards really figuring anything out. The energy in an arc is not solely
determined by its length either, as you can have different amounts of current
flowing through the arc, and thus very different amounts of energy.
I'm not trying to insult you, John, but there are several very fundamental
mistakes in the calculations you have done (specifically in calculating voltage,
current, etc. in the secondary), and you should really try to read up on how the
quantities interact/relate. One definite flaw was "Secondary current =
joules/voltage". I'm not going to use more time/bandwidth of the list, and I'm
sure several people are getting tired of this discussion, so I'll leave this
discussion with this: True power ratings are a very good estimator of how much
power is getting to the actual coil for the same type, i.e., SGTC, SSTC,
etc. To compare Steve's ISSTC to a SGTC with the same power input that gets
half of the spark length tells me that either a) The losses in the ISSTC are
much lower, or b) the output waveform of ISSTC is such that it is able to
facilitate streamer growth to a much greater extent than the SGTC, and for the
purposes of the hobby, I would consider either scenario to be much more
efficient than the SGTC! Sean Taylor, Urbana, IL
Date : Wed, 23 Jun 2004 22:46:15 -0600
Original
poster: Mddeming@aol.com
In a message dated 6/23/04
11:33:27 PM Eastern Daylight Time, tesla@pupman.com writes:
Giving an efficiency in power makes perfect sense. Most devices are rated in
this way. A motor has a certain electrical power in, and a certain mechanical
power output. The efficiency is defined as Mechanical power out / electrical
power in. A heater, lightbulb, and many other devices can be given an
efficiency rating the same way! What doesn't make sense is to say we have a
motor which has a certain power output, and then try to calculate the energy
output by lifting a mass, or some other means and at the same time monitoring
the input power and integrating - much more of a pain, and will arrive at
(approximately, due to measurement error) the same result.
Hi Sean, Power makes sense for the devices you cite, but only because they are
fairly constant and continuous power-in, power-out devices with a load that can
be held constant during testing. None of this applies to a Tesla coil. The
input and output occur at different times, are of different durations, different
waveforms, different frequencies. In this case, a good argument for energy
measurement can be made. Matt D.
Date : Wed, 23 Jun 2004 22:48:01 -0600
Original
poster: "john cooper"
<tesla@tesla-coil.com>
Does this enigma basically boil down to timing issues (once we resolve the
vernacular)? And the difficulty in tuning/measuring same throughout the
system? I'm intentionally leaving out the other dozen(s) variables. Jeez, what a
can of worms, I only have two storage scopes, that's not enough. We need an X
prize for this one, where's Paul Allen when we need him? And all 3 or 4 left
standing can applaud.
John
Date : Thu, 24 Jun
2004
08:59:08
-0600
Original
poster: "Steve Conner"
<steve.conner@optosci.com>
>I agree wholeheartedly.
And me! The whole energy vs. power thing is just a red herring. You can convert
between energy and power at will, by just integrating or differentiating with
respect to time. You should get the same answer for efficiency of your coil no
matter which method you use.
Of course, by efficiency, I mean (power delivered to discharge/power drawn from
wall socket). The relationship between power delivered to discharge, and length
of discharge, is a different ballgame altogether, and we understand it a lot
less.
But I still think, from experimental evidence, that power is a better way of
rating things. Freau's formula (spark length that you get about once a minute=
1.7* square root of power input) works remarkably well.
It works because the spark length, though random, obeys statistical laws. So
the big strike that you get once a minute is related in a predictable way to the
controlled spark length that John Couture is so fond of.
There is no comparable formula that works in terms of energy only. That is
because the spark length achieved by a given energy depends on how fast the
energy is delivered, i.e. the power.
For instance, if I discharge a single 8 joule shot of energy into a pulsed SSTC
over a half-hour period (a power of 4.4 milliwatts) I'll get no sparks at all.
But if I do it in 60 microseconds (a power of 133 kilowatts) I get a deafening
BANG! and a 24" streamer.
Of course, if I set my coil to let off one of these 8 joule, 60 microsecond
discharges every half hour, the average power consumed by the coil would still
only be 4.4 milliwatts and yet it would be doing 24". This
demonstrates why Freau's formula loses accuracy for BPS other than 120.
Confused yet? :)))))).
Steve C.
Date : Thu, 24 Jun 2004 09:01:38 -0600
Original
poster: Sean Taylor
<sstaylor@uiuc.edu>
Hi Matt,
I agree with what you say, to a point. First, I was simply refuting the
statement that efficiency based on power doesn't make sense (loosely
paraphrased). It is hard to determine the "efficiency" of a TC, since as you
say, it is quite a dynamic machine. What I did/would suggest, if one were
interested in the strict efficiency (and it was possible to measure the output
easily), would be to use an energy type of approach as I said about a single
shot mode. However, this doesn't really apply to streamer growth which happens
over successive bangs and doesn't have a predictable pattern - ie "the streamer
will be at 85% of the full length after exactly 14 consecutive bangs". There is
a lot more that comes into play, and I think an average power approach
compromises enough in order to include enough of the fluctuations. Of course,
there isn't a really good way to measure the output power of a TC, so we end up
using streamer length frequently, and end up with no "real" units of efficiency,
but rather a performance "guideline".
As has been stated many times implicitly, and now I'll make it explicit, (in my
opinion) and energy measurement is useful for an isolated, controlled
instance. The power measurement will cover a more continuous timeframe and does
not consider the amount of time so much as the rate of transfer. This is
evident in the units - energy is N-m (- meaning multiplied), while power is
N-m/s. Power is just a rate, like m/s, and doesn't give a specific quantity,
but rather an idea of how fast you're getting to a specific quantity. I suppose
one could frame the question of power as "How long does it take for a TC to
transform X kJ of energy (into another form)?". Anyway, enough of this topic
:-) I think I and others have probable done as much to confuse the issue as we
have to make any more sense! Sean Taylor
Date : Thu, 24 Jun
2004
09:01:26
-0600
Original
poster: "Malcolm Watts"
<m.j.watts@massey.ac.nz>
Hi Matt,
Below I'll give two clear examples of why I left energy considerations behind in
the dust wrt TCs:
On 23 Jun 2004, at 22:46, Tesla list wrote:
> Original poster: Mddeming@aol.com
>
> In a message dated 6/23/04 11:33:27 PM Eastern Daylight Time, tesla@pupman.com
writes:
>
> Giving an efficiency in power makes perfect sense. Most devices are rated in
this way. A motor has a certain electrical power in, and a certain mechanical
power output. The efficiency is defined as Mechanical power out / electrical
power in. A heater, lightbulb, and many other devices can be given an
efficiency rating the same way! What doesn't make sense is to say we have a
motor which has a certain power output, and then try to calculate the energy
output by lifting a mass, or some other means and at the same time monitoring
the input power and integrating - much more of a pain, and will arrive at
(approximately, due to measurement error) the same result.
Hi Sean,
Power makes sense for the devices you cite, but only because they are fairly
constant and continuous power-in, power-out devices with a load that can be held
constant during testing. None of this applies to a Tesla coil. The input and
output occur at different times, are of different durations, different
waveforms, different frequencies. In this case, a good argument for energy
measurement can be made. Matt D.
40J (for example) can give a totally different sparklength under the following
situations:
#1 - a single shot of 40J into cold air vs a shot of 40J into a hot,
well-established streamer path
#2 - 40J under either situation coming from substantially different secondary
coils, i.e. the L/C ratios and hence output voltages for one thing being totally
different. Malcolm.
Date : Thu, 24 Jun
2004
09:00:01
-0600
Original
poster: Yurtle Turtle
<yurtle_t@yahoo.com>
This is the second time I've seen someone refer to "Watts
per second". What's that? A Watt is simply a
Joule per second. A Joule is energy. A Watt is power. What would Watts/second
be? Joules per second squared?
To get energy, one multiplies time with power, or Watts * time to get something
like kilowatt hours.
I'm confused. Adam
--- Tesla list
<tesla@pupman.com> wrote: Original poster: Sean Taylor
<sstaylor@uiuc.edu>
<snip>
> 3) Wattmeters don't give you Watts/sec, just watts, that's it!
</snip>
> Sean Taylor, Urbana,
IL
Date : Thu, 24 Jun
2004
08:59:33
-0600
Original
poster: "Steve Conner"
<steve.conner@optosci.com>
>Coil A puts out 10 foot arcs with only 1kW RMS power measured at the plug.
Coil B puts out 5 foot arcs with the same 1kW RMS power measured at the plug.
This post of Dan's was a good example of what I was saying about spark length
obeying statistical laws. If Coil B strikes 5ft once a minute, then I know, and
I'm sure most of you will agree, it's not going to produce a freak spark that
beats Coil A's 10ft, even if I run it non-stop for six months.
In other words, the whole gamut of spark types, from 120 hits-a-second
"controlled spark", to the freak "holy cow did you see that", seem to happen
over a fairly narrow range of toroid-to-target distances. So for instance if I
place a target 5ft away from my big OLTC, it will just be a solid power arc, but
at 6ft, it will hit it maybe once or twice a minute.
However, my experience is with OLTCs, SSTCs, and DC spark-gap coils, which have
a very constant and predictable bang energy. With an ASRG or static gap system,
things get more chaotic, and I expect the distance between solid power arcing
and occasional hits will get greater. I haven't done the experiment, but
my gut feeling is that if we plotted the frequency of hits vs. the
toroid-to-target distance, all suitably normalised, we would get an energy
distribution like the Fermi-Dirac distribution
http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/disfd.html#c3
except with distance as the variable rather than energy. The "temperature" in
the F-D equation would be a constant that described the randomness of streamer
growth in general, and the randomness of bang energies in your coil.
If this was the case, then the most logical way of rating your coil would be by
quoting a "Fermi Distance" and a temperature 8-P
Or we could just forget about it and go blow some more IGBT’s. Steve C.
Date : Thu, 24 Jun
2004
18:50:57
-0600
Original
poster: "John Couture"
<johncouture@bellsouth.net>
Sean - You are right. I really messed up that post. Not enough checking of what
I thought I said. What of the post I sent to Matt? John Couture
----------------------------------------
Sent: Wednesday, June 23, 2004 10:22 PM
Subject: Re: SSTC does 10 foot sparks
> Original poster: Sean Taylor
<sstaylor@uiuc.edu>
>
> I've gotta reply to this . . .
>
> On Wed, 23 Jun 2004 11:21:47 -0600, Tesla list
<tesla@pupman.com> wrote: If you are rating your TC in power units
(watts) it does not make engineering sense to say the efficiency is equal to
anything. Efficiency refers to energy units not to power units. However, if you
are rating your TC in power units it does make sense to say it has a power gain
of a certain amount. You can then use this number to compare with other TC's.
>
> Giving an efficiency in power makes perfect sense. Most devices are rated in
this way. A motor has a certain electrical power in, and a certain mechanical
power output. The efficiency is defined as Mechanical power out / electrical
power in. A heater, lightbulb, and many other devices can be given an
efficiency rating the same way! What doesn't make sense is to say we have a
motor which has a certain power output, and then try to calculate the energy
output by lifting a mass, or some other means and at the same time monitoring
the input power and integrating - much more of a pain, and will arrive at
(approximately, due to measurement error) the same result.
>
> >The above, of course, does not solve the problem of how to properly test and
rate a Tesla coil when using spark length as the TC output. In the past only a
few coilers could rate and test their coils properly. This resulted in shorter
sparks. However, everyone was more impressed by that random extra long spark so
any tests that gave shorter sparks were not popular. The problem was the true
input energy that actually created that special extra long spark could not be
determined so true TC comparisons could not be made. Only continuous sparking
with fixed lengths made sense. But it does not appear that we will ever get away
from that mysterious random extra long spark test with an unknown input ( except
maybe for one shot tests). John Couture
>
>
> What is rating a coil "properly"? The only way to have a relatively constant
bang energy is to use a triggered type of gap (rotary, etc.) and then how do you
calculate the energy in and out? What is rated "properly" such that the coil
ran with a "constant" length spark? As line voltage fluctuates, and
environmental conditions change, so will the spark length on the output, and
there is no "rating" that will change that. I am interested to know what you
are suggesting changing on a coil that would "rate it properly". Do you have
any documented proof that this was done, or what was changed?
>
> In your other post regarding the energy in a single spark, I'm sorry to say,
but that is complete bull. There are several problems with the logic > - 1) How
was the breakrate known to be 120? 2) The system definitely isn't >
lossless!!! 3) Wattmeters don't give you Watts/sec, just watts, that's it! 4)
There is streamer growth over successive bangs, so unless you know the voltage
you charged the tank gap too, are running ina single shot type of set up, and
know the exact losses of the system, there is no way to know the energy in the
8.25" arc!! As you state, there IS a lot more, but the problem is this isn't
even a start towards really figuring anything out. The energy in an arc is not
solely determined by its length either, as you can have different amounts of
current flowing through the arc, and thus very different amounts of energy.
>
> I'm not trying to insult you, John, but there are several very fundamental
mistakes in the calculations you have done (specifically in calculating voltage,
current, etc. in the secondary), and you should really try to read up on how the
quantities interact/relate. One definite flaw was “Secondary current =
joules/voltage". I'm not going to use more time/bandwidth of the list, and I'm
sure several people are getting tired of this discussion, so I'll leave this
discussion with this: True power ratings are a very good estimator of how much
power is getting to the actual coil for the same type, ie SGTC, SSTC, etc. To
compare Steve's ISSTC to a SGTC with the same power input that gets half of the
spark length tells me that either a) The losses in the ISSTC are much lower, or
b) the output waveform of ISSTC is such that it is able to facilitate streamer
growth to a much greater extent than the SGTC, and for the purposes of the
hobby, I would consider either scenario to be much more efficient than the SGTC!
Sean Taylor Urbana, IL.
Date : Thu, 24 Jun 2004 18:51:28 -0600
Subject : Re: SSTC does 10 foot sparks
Original poster: "Gerry Reynolds"
<gerryreynolds@earthlink.net>
In general, I support standard methods of measuring things. The controlled
single bang spark length that John Couture is fond of is find in so far as it
goes. It certainly is a measure of how well a charged Cp with a certain bang
energy results in a spark of a certain length, but this is only part of the
story. It does nothing for characterizing streamer growth due to multiple bangs
nor the accumulative effect that multiple bangs have on the sparkgap efficiency
(heating and quenching for example). Gerry R.
> Original poster: "Steve Conner"
<steve.conner@optosci.com>
>
> But I still think, from experimental evidence, that power is a better way of
rating things. Freau's formula (spark length that you get >about once a minute=
1.7* square root of power input) works remarkably well.
>
> It works because the spark length, though random, obeys statistical laws.
So the big strike that you get once a minute is related >in a predictable way to
the controlled spark length that John Couture is so fond of.
Date : Thu, 24 Jun 2004 18:51:39 -0600
Original
poster: "Gerry Reynolds"
<gerryreynolds@earthlink.net>
Hi Adam, Don't be confused, I don't think the writer meant watts per
second. In any case, this has no relavent meaning to this discussion as watts
per second is a measure of rate that power is changing (dP/dt).
Gerry R
> Original poster: Yurtle Turtle
<yurtle_t@yahoo.com>
>
> This is the second time I've seen someone refer to "Watts
per second". What's that? A Watt is simply a
> Joule per second. A Joule is energy. A Watt is power. What would Watts/second
be? Joules per second squared?
>
> To get energy, one multiplies time with power, or Watts * time to get
something like kilowatt hours.
>
> I'm confused. Adam
>
> > Original poster: Sean Taylor
<sstaylor@uiuc.edu>
<snip>
> > 3) Wattmeters don't give you Watts/sec, just watts, that's it!
>
> </snip>
>
> > Sean Taylor Urbana, IL
Date : Thu, 24 Jun
2004
18:49:05
-0600
Original
poster: Mddeming@aol.com
In a message dated 6/24/04 11:07:43 AM Eastern Daylight Time, tesla@pupman.com
writes:
40J (for example) can give a totally different spark length under the following
situations:
#1 - a single shot of 40J into cold air vs a shot of 40J into a hot,
well-established streamer path
#2 - 40J under either situation coming from substantially different secondary
coils, i.e. the L/C ratios and hence output voltages for one thing being totally
different. Malcolm
Hi Malcolm, All, Sounds like "A non-linear dynamical system critically dependent
upon initial conditions, i.e. chaos." If this is so, then there can be no
complete, closed, deterministic form for describing the operation of a TC, and
the debate starts to resemble the Mandelbrot set, i.e no matter how close you
look at it, there are still infinite convolutions and there can be
no resolution. The debate must therefore be infinite :-(( Matt D.
Date
: Thu, 24 Jun 2004
18:51:48
-0600
Original poster: "John Couture"
<johncouture@bellsouth.net>
Adam - Because of a typo I used the wording "watts per second" and that wording
is incorrect. I meant watt seconds which is correct wording. However, "watt
seconds per second" would be correct which also means joules per seconds.
However, if you interpret this to be
Watts
x seconds / seconds
It is obvious that the "seconds" cancel out and you end up with "watts" only. It
is also obvious that "per" and "/" or "division" are in conflict. But how about
Joules per second or Joules / seconds
Seconds do not cancel out. Does this mean that Watts per second do not equal
joules per second?
and Watt x seconds do not equal joules? John Couture.
Date : Thu, 24 Jun
2004
18:51:09
-0600
Original poster: "John Couture"
<johncouture@bellsouth.net>
John - I think it is a matter of deciding how to handle the Tesla coil output
when the output is in sparks. Maybe we should just test the TC output with a
resistive load like most electrical generators are tested. Loading the TC output
reduces the voltage to any voltage and current combination you want. The input
and output would be continuous and easy to measure. This has been suggested in
the past but there was not much coiler interest. John Couture
----------------------------------------
Date : Thu, 24 Jun
2004
21:01:11
-0600
Original
poster: "Godfrey Loudner"
<ggreen@gwtc.net>
Hello John: They use to load tesla coils with x-ray tubes. Heating up the
filament to the proper level for a given tube, the current through the tube
could perhaps be measured. Maybe this sort of data could be worked back to say
something about output. Of course, shielding from x-rays would be a problem.
Godfrey Loudner
>Maybe we should just test the TC output with a resistive load like most
electrical generators are tested.
John Couture
Date : Tue, 22 Jun 2004 20:15:32 -0600
Subject : power v energy measurements, was Re: SSTC
does 10 foot sparks
Original poster: Sean Taylor
<sstaylor@uiuc.edu>
John, I'm not really in agreement with you, the examples I gave (specifically
the 30 MJ) were to illustrate that two different coils,
consuming vast differences in power, can be given the same "energy rating". How
do you propose to use energy? Would you like to use energy per bang, or energy
over a certain amount of time? Both of those can be translated into
power. What specific measurement of energy did you have in mind?
Any meter, when used on a TC, will have fluctuations in the reading with the
target a streamer happens to be striking at that moment. If a power meter is
used, then the power will jump all over the place. The best we can do is to
estimate an average power, where it seems that the needle is most of the time,
or more accurately is expected to be most of the time. I believe that
strict energy comparisons have no place in comparing TC's without another
parameter to give more information (as in my example cited
in my first post on this topic - two very different TC's with the "same"
energy).
In your reply to Steve, you wrote:
Power output can be greater than power input
Power is in watts, average watts, peak watts, volt amps, etc.
Energy output can not be greater than energy input
Energy is in watt seconds or joules*
The power input can be in many forms as I mentioned in my post to
Gerry.
The energy input can be in only one form and that is watt seconds
(joules).*
Power factor is involved with TC power ratings
Power factor is not involved with TC energy ratings.* Why??
I would say all but three of these statements are false (when taken in certain
ways). I would consider the three true statements to be the ones marked with an
*. Power output can be greater than power input, if you are speaking of peak
power. Power is not in volt amps - that is apparent power. Just power is
Watts, and only watts. Units themselves cannot be average, peak, etc., only a
quantity can. I know this is beginning to get into semantics, but you state
that energy only comes in one form, and the same is true of power. It's always
just Watts (or some equivalent unit), nothing else. The power input can't be in
many forms, but the measurement can be *represented* in a few different ways,
and I think that's where the confusion lies. As I said before, each
representation (peak, average, etc.) has it's place in each application. For
comparison purposes in the TC world, we'll want to be using average power for
the input.
Power factor doesn't/shouldn't come in to play here because power is power -
regardless of the power factor. Apparent power on the other hand (simple
current * voltage), will change with the power factor, given a constant
power. So if we know exactly how much work is being done by a system, we can
calculate the apparent power based on the power factor.
For most of us, it is hard to get a good idea of what the real power is because
all we have is a voltmeter and ammeter, and they tell us nothing of the phase
relationship, and thus nothing of the power factor. All we can then calculate
is the the apparent power and all we can do with this is get an approximation of
the real power. As Steve said, he is drawing less than 20 A at 240 volts, so
the apparent power must be less than 4800 VA, and the real power cannot exceed
the apparent power, so it must be less than 4800 W
(note the unit change - Watts != VA !!!).
Now, to make the leap to energy, well, the problem is how?? As I already asked,
which energy did you want to measure? Even fewer of us have the necessary
equipment to measure energy directly (aside from the energy meter on the outside
of our house). You wrote in another email "Energy is not involved with reactive
powers.", while it most certainly is!!! It is not transferred in one direction
though, because it continuously is transferred in to and out of the reactive
component, and part of it gets wasted as heat each time that happens (in the
real, non-ideal world).
Anyway, this discussion is starting to get a bit OT, if you want to continue it
with me, please reply off list.
Sean Taylor, Urbana, IL
Date : Wed, 23 Jun 2004 11:23:41 -0600
Subject : Re: power v energy measurements, was
Re: SSTC does 10 footsparks
Original poster: "John Couture"
<johncouture@bellsouth.net>
Sean -
You do not have to agree with me to be right. As I mentioned before in the past
I have used the word "power" incorrectly. This is very easy to do and it occurs
in today's literature all the time. For example power cannot be consumed. This
is why electric power companies do not sell power, they sell energy. Some
coilers have said that the utility "demand charge" is selling power. This is not
correct. The demand charge is a rental charge for large transformers and related
switchgear.
"How do I propose to use energy?" There are many possibilities. However, I
believe the best way to compare Tesla coils is to do it the energy way, not the
power way. I will give an example using a small coil I built and tested. I
don't have a SSTC to make a comparison but I know there are many coilers who
have both types who could easily do the tests and make the comparison.
The tests consist of finding the TC input energy by connecting a wattmeter to
the input of the TC. This will give you input watts per second (joules).
You then turn up the variac so you have 120 watt seconds input and adjust the
spark output for a continuous 120 sparks per second. You will then have 120 watt
seconds / 120 sparks per second giving you "one joule per spark" or "spark
inches per joule of energy". I did this for my small TC and obtained 8.25
inches per joule. If you perform this test with with any small
SPTC or SSTC you will have a fair energy comparison of the Tesla coils. Of
course the 120 sparks per second would have to be changed to the actual number
per second.
As I have mentioned in the past this leaves a lot to be desired and I am open to
all suggestions. When larger coils are tested you will find that the "spark
length per joule" is much shorter but there is a good reason for this which can
be discussed later.
This test also gives you some other interesting numbers about your TC. For
example with my coil I found the energy in the 12" toroid (about 13 picofarads)
was 1 joule per spark. This gave me
Secondary voltage = .5 x sqrt(joules/Cs)
= .5 x sqrt(1joule / 13^-12)
Secondary voltage = 392 KV at 100% eff.
I assumed the secondary voltage eff was about 50% so the secondary voltage was
Secondary voltage = 392 x .5 = 196 KV
If I connected an ammeter to the ground wire of the secondary coil I would get
Secondary current = joules/voltage = 1/196000
Secondary current = 5.1 uA
Note that this is the average (RMS) current in the secondary of my small coil.
The actual peak current would be much greater. If I found the average current by
test was larger I could then find the true secondary voltage which would be
higher than 196 KV.
You can find even more TC parameters if you use energy instead of power for
rating your coils. John Couture.
Date : Wed, 23 Jun 2004 16:54:12 -0600
Subject : Re: power v energy measurements, was
Re: SSTC does 10 footsparks
Original poster: "Eastern Voltage Research Corporation"
<dhmccauley@easternvoltageresearch.com>
This energy stuff is just going to far. As a power engineer who designs high
power transmitters, high power and high voltage power supplies, and a boatload
of DC-DC converters, I have not once ever heard anyone make a reference to
energy.
Its all about power! Dan.
Date : Wed, 23 Jun 2004 21:23:24 -0600
Subject : Re: power v energy measurements, was
Re: SSTC does 10 footsparks
Original poster: Mddeming@aol.com
Hi John, All, My comments interspersed.
In a message dated 6/23/04 1:34:26 PM Eastern Daylight Time, tesla@pupman.com
writes:
>The tests consist of finding the TC input energy by connecting a wattmeter to
the input of the TC. This will give you input watts per second (joules).
Watts per second is not Joules. Watt seconds is Watts TIMES seconds = Joules.
Watts per second is Watts DIVIDED by Seconds.Watts per second is therefore
Joules per second squared, or some sort of "acceleration of energy", or
"velocity of power", or some such meaningless quantity.
>You then turn up the Variac so you have 120 watt seconds input and adjust the
spark output for a continuous 120 sparks per second. You will then have 120 watt
seconds / 120 sparks per second giving you "one joule per spark"
Unfortunately, 120 watt seconds/120 sparks per second would be (120 W. sec) /120
spark/sec = 1 Watt sec^2
I think what you meant is 120 Watts / 120 sparks/Sec = (120 Joules/sec)/(120
sparks/sec) = 1 Joule/spark which is dimensionally consistent.
Inverting this does give you sparks/joule. Assuming all sparks are the same size
and that each spark contains energy from exactly one-half input cycle, your
formula holds.
>or "spark inches per joule of energy". I did this for my small TC and obtained
8.25 inches per joule. If you perform this test with any small SPTC or SSTC you
will have a fair energy comparison of the Tesla coils. Of course the 120
sparks per second would have to be changed to the actual number per second.
I like your concept, and fortunately the mistakes in nomenclature and the
mistakes in math exactly canceled out to give you the answer you seek, but I
would hate for anyone with a shaky understanding of math and physics to have to
follow the development. ;^)
Matt D.
Date : Wed, 23 Jun 2004 22:45:38 -0600
Subject : Re: power v energy measurements, was
Re: SSTC does 10 footsparks
Original poster: "Malcolm Watts"
<m.j.watts@massey.ac.nz>
On 23 Jun 2004, at 16:54, Tesla list wrote:
> Original poster: "Eastern Voltage Research Corporation"
>
<dhmccauley@easternvoltageresearch.com>
>
> This energy stuff is just going to far. As a power engineer who designs high
power transmitters, high power and high voltage power supplies, and a boatload
of DC-DC converters, I have not once ever heard anyone make a reference to
energy.
> Its all about power! Dan.
Absolutely agree. All the appliances I've ever come across are rated in units of
power based on a figure such as continuous
consumption (e.g. light bulbs, heaters) or maximum (peak) power consumption
(e.g. audio amplifiers) when running from a more-or-less fixed voltage (e.g.
240VAC mains). I find nothing confusing about such ratings. For one thing, it
tells me what fuse ratings should apply.
The power consumption of a Tesla Coil inevitably varies but knowing that one can
obtain several strikes of a certain length over
some nominated period of time without popping a breaker of a particular current
rating is the figure I'd consider relevant and
useful. I once made a statement about sparklength/energy rating, a move I left
behind years ago after developing a much deeper
understanding of the dynamics involved. The passage below reads like a supreme
exercise in obfuscation to me. Malcolm.
Date : Thu, 24 Jun 2004 08:58:46 -0600
Subject : Re: power v energy measurements, was
Re: SSTC does 10 footsparks
Original poster: Chris Roberts
<quezacotl_14000000000000@yahoo.com>
Hello everybody,
Well, I hope that I can explain this correctly and that it will make sense to
everyone...
Okay, I understand the argument for rating coils by energy. For an extreme
example, (I know that this can't practicably happen in real life, it is just an
extreme example to better visualize everything) we can have somebody's coil
charge at 1 watt for months, then release it all in a split second in a
tremendous mega-joule bang that would give you one heck of a spark. One the
other hand, you can get somebody who plugs their coil right into the output of a
multi-megawatt nuclear plant and get the same spark in a fraction of the time.
Now, from a wattage standpoint, it looks like the former coil is more efficient.
In real life though, our coils run at a relatively constant bps speed. I
mean, even if Steve's coil was running at something like 25 bps with massive
bang sizes it still would look constant to the naked eye. And that is
really all that we are shooting for, right? I mean, if you are stressing
your house's electrical mains and you can't increase the power input for fear of
melting your wires in the house, but figure out how to push a few inches of
spark by kicking the bang sizes up, then in my mind that is being more
efficient. After all, in the end we all are just trying to make the sparks as
big as possible. =D -Chris Roberts.
Date : Thu, 24 Jun 2004 08:58:25 -0600
Subject : Re: power v energy measurements, was
Re: SSTC does 10 footsparks
Original poster: Bart Anderson
<tesla111@sbcglobal.net>
Hi All,
I too have taken the side of finding this topic pretty much useless. The
battle of power and energy comes up on the TCML far too often. There are
those here who just love to research the physics (I'm in that category), yet
others find that stuff boring. Even though I love the research, it is clear we
will never be able to compare coils one for one. The best we can do as a
"comparison" is simple average power measurements for a given spark length (and
maybe a few tid-bits about break rates and losses). Efficiency
comparisons are not possible in this type of forum (as great as it is).
Those type of comparisons have to be performed in a controlled project
environment with the same engineers making comparisons with whatever units of
measure they choose to define. But not across a large forum like this.
There are just too many dynamics (and I'm not talking only of coil dynamics).
It is fun to read the posts however (kind of a love/hate thing). Take
care, Bart.
Date : Thu, 24 Jun 2004 18:51:19 -0600
Subject : Re: power v energy measurements, was
Re: SSTC does 10 footsparks
Original poster: "John Couture"
<johncouture@bellsouth.net>
Bart -
I am begin