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Slide Choke

 

Updated:  July 29,2006

 

Check out my slide choke on this page:  www.Tesla-Coil.com/Reactor.htm

and :  www.tesla-coil.com/Ballasting.htm

 

 

 

Date:  Sun, 30 Apr 2006 15:04:34 -0600

From:  Tesla list <tesla@pupman.com>

To:  tesla@pupman.com

Subject:  Slide choke

 

Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>

A while ago I successfully built a slide choke using a 500 Ft spool of #10 thhn house wire, and coated mild steel tig rods, cut to 12". I have acquired some "I" laminations that are 1 3/4 inches wide, and 18"  long. I have enough to make 2 , 1 3/4 square cores. I have about 750 ft. of #8 PVC wire. Is the length/width ratio of the coil a major factor? In other words, can I wind an 18" long coil with the wire I have, and just use the laminations as is? I'll be using this with 240v, up to 50 A Initially, and maybe 90A later.

 

 

 

 

Date:  Sun, 30 Apr 2006 16:17:44 -0600

From:  Tesla list <tesla@pupman.com>

To:  tesla@pupman.com

Subject:  Re: Slide choke

 

Original poster: "D.C. Cox" <resonance@jvlnet.com>


Mike:

You will probably be able to use this successfully up to 30-35 Amperes. Even with our reactors, due to choke intermittant saturation, running at 30 Amps were must use at least #10 AWG 150 degree C. magnet wire and a small 200 cfm blower fan blasting air into the windings( we spacewind each layer with some 1/4 x 1/4 inch cut fiberglass rods to allow the fan airflow thru the coil).  We use Nomex insulation layer to layer to provide some thermal separation between layers.  At 12 AWG, the wire starts to overheat substantially.  At your proposed range of 50 Amps you will probably have to go down to #6 AWG 150 degree C. magnet wire.

Another idea might be to make up some flat endplates/endcaps for a 4 inch dia. PVC tube.  These endplates would be 1/4 inch thick, circular, and have a dia of perhaps 10 inches.  Then the wire would be spooled off the Home Depot 500 ft spool onto your newly created coilform.

With some tinkering I think you could come up with a nice design that would use a fixed, non-moveable core, and perhaps 300-500 turn range of #10 AWG Home Depot house wiring.  Starting with 500 turns keep removing wire until you hit the 30-35 Ampere range.  This would be a nice series reactor for use with pole pigs powering a .05 to .07 uF range cap bank and running at 7.5 kVA approx range.

This sounds like an interesting idea.  I plan to also experiment with it using some tapped Supercil 10 silicon steel cores this summer when I get back to WI after May 15th.  If you have some time off during the week, perhaps you could come up to our shop and we will do some work together on this idea. 
Regards,

Dr. Resonance

 

 

 

 

Date:  Thu, 18 May 2006 12:18:59 -0600

From:  Tesla list <tesla@pupman.com>

To:  tesla@pupman.com

Subject:  Slide choke - second request for advise !!

 

Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>


----- Original Message -----
From: "Tesla list" <tesla@pupman.com>
To: <tesla@pupman.com>
Sent: Sunday, April 30, 2006 4:04 PM
Subject: Slide choke


> Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>
 >

I apologise for re-posting this question, but never received an answer to my real question. (On a side note, DC's invite to investigate this experimentally is very intriuging, lets talk off-list about this further). So please read
all of this, including the additional question below. THANKS !!

> A while ago I successfully built a slide choke using a 500 Ft spool
> of #10 thhn house wire, and coated mild steel tig rods, cut to 12". I
> have aquired some "I" laminations that are 1 3/4 inches wide, and 18"
> long. I have enough to make 2 , 1 3/4 square cores. I have about 750
> ft. of #8 PVC wire. Is the length/width ratio of the coil a major
> factor? In other words, can I wind an 18" long coil with the wire I
> have, and just use the laminations as is, or should I wind shorter,
and fatter? I'll be using this with  240v, up to 50 A Initially, and maybe 90A later.  My second question, is weather I can weld the lamination stack together at the edges? I see this done with MOT's all the time.

 

 

 

 

Date:  Thu, 18 May 2006 15:05:27 -0600

From:  Tesla list <tesla@pupman.com>

To:  tesla@pupman.com

Subject:  Re: Slide choke - second request for advise !!

 

Original poster: "Mike" <mike.marcum@zoomtown.com>

I guess it depends on what your goals are. If weight/cost is not a consideration and your going for max efficiency (mostly L with little R) then the core would be close to cube shaped with 1:1 turns ratio.
Most are longish for economic/weight reasons. If you don't mind losing a few more watts of heat and having a bit more of a voltage drop, use what you have.  As far as welding laminations, that also makes little difference.
Maybe a few watts  in eddy currents there out of 12kW+ (most of the flux is in the center and not the corners/outer edges of the cross-section), as long as the bead is thin.

Mike
----- Original Message ----- From: "Tesla list" <tesla@pupman.com>
To: <tesla@pupman.com>
Sent: Thursday, May 18, 2006 2:18 PM
Subject: Slide choke - second request for advise !!


>Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>
>
>
>----- Original Message -----
>From: "Tesla list" <tesla@pupman.com>
>To: <tesla@pupman.com>
>Sent: Sunday, April 30, 2006 4:04 PM
>Subject: Slide choke
>
> > Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>
> >
>I apologise for re-posting this question, but never received an answer to
>my real question. (On a side note, DC's invite to investigate this experimentally
>is very intriuging, lets talk off-list about this further). So please read all of
>this, including the additional question below. THANKS !!
>
> > A while ago I successfully built a slide choke using a 500 Ft spool
> > of #10 thhn house wire, and coated mild steel tig rods, cut to 12". I
> > have aquired some "I" laminations that are 1 3/4 inches wide, and 18"
> > long. I have enough to make 2 , 1 3/4 square cores. I have about 750
> > ft. of #8 PVC wire. Is the length/width ratio of the coil a major
> > factor? In other words, can I wind an 18" long coil with the wire I
> > have, and just use the laminations as is, or should I wind shorter,
>and fatter? I'll be using this with  240v, up to 50 A Initially, and maybe 90A later.
>My second question, is weather I can weld the lamination stack
>  together at the edges? I see this done with MOT's all the time.
> >

 

 

 

 

Date:  Fri, 19 May 2006 10:35:30 -0600

From:  Tesla list <tesla@pupman.com>

To:  tesla@pupman.com

Subject:  Re: Slide choke - second request for advise !!

 

Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>

Thanks mike. I'll go ahead and wind it long and narrow. The real problem with the laminations is that the stack tends to bulgein the middle. This is where They need the weld bead. You said the middle is where theflux is most severe, but I think you mean the inside of the core. So is a bead on the outside of the center of the core ok?Original poster: "Mike"
mike.marcum@xxxxxxxxxxxx

I guess it depends on what your goals are. If weight/cost is not a consideration and your going for max efficiency (mostly L with little R) then the core would be close to cube shaped with 1:1 turns ratio. Most are
longish for economic/weight reasons. If you don't mind losing a few more watts of heat and having a bit more of a voltage drop, use what you have. As far as welding laminations, that also makes little difference. Maybe a few
watts in eddy currents there out of 12kW+ (most of the flux is in the center and not the corners/outer edges of the cross-section), as long as the bead is thin.


----- Original Message -----
From: "Tesla list" <tesla@pupman.com>
To: <tesla@pupman.com>
Sent: Thursday, May 18, 2006 1:18 PM
Subject: Slide choke - second request for advise !!


> Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>
 >
 >
> ----- Original Message -----
> From: "Tesla list" <tesla@pupman.com>
> To: <tesla@pupman.com>
> Sent: Sunday, April 30, 2006 4:04 PM
> Subject: Slide choke
 >
 >
>  > Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>
>  >
 >
> I apologise for re-posting this question, but never received an answer to
> my real question. (On a side note, DC's invite to investigate this experimentally
> is very intriuging, lets talk off-list about this further). So please read all of
> this, including the additional question below. THANKS !!
 >
>  > A while ago I successfully built a slide choke using a 500 Ft spool of #10 thhn house wire, and coated mild steel tig > >rods, cut to 12". I have aquired some "I" laminations that are 1 3/4 inches wide, and 18" long. I have enough to make > >2 , 1 3/4 square cores. I have about 750 ft. of #8 PVC wire. Is the length/width ratio of the coil a major factor? In other > >words, can I wind an 18" long coil with the wire I have, and just use the laminations as is, or should I wind shorter,
> >and fatter? I'll be using this with  240v, up to 50 A Initially, and maybe 90A later.   My second question, is weather I  > > >can weld the lamination stack together at the edges? I see this done with MOT's all the time.
>  >

 

 

 

 

Date:  Fri, 19 May 2006 15:28:30 -0600

From:  Tesla list <tesla@pupman.com>

To:  tesla@pupman.com

Subject:  Re: Slide choke - second request for advise !!

 

Original poster: "Mike" <mike.marcum@zoomtown.com>

yup, that's fine.

Mike
----- Original Message ----- From: "Tesla list" <tesla@pupman.com>
To: <tesla@pupman.com>
Sent: Friday, May 19, 2006 12:35 PM
Subject: Re: Slide choke - second request for advise !!


>Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>
>
>Thanks mike. I'll go ahead and wind it long and narrow. The real problem
>with the laminations is that the stack tends to bulgein the middle. This is
>where They need the weld bead. You said the middle is where theflux is most
>severe, but I think you mean the inside of the core. So is a bead on the
>outside of the center of the core ok?Original poster: "Mike"
>mike.marcum@xxxxxxxxxxxx
>
>I guess it depends on what your goals are. If weight/cost is not a
>consideration and your going for max efficiency (mostly L with little R)
>then the core would be close to cube shaped with 1:1 turns ratio. Most are
>longish for economic/weight reasons. If you don't mind losing a few more
>watts of heat and having a bit more of a voltage drop, use what you have. As
>far as welding laminations, that also makes little difference. Maybe a few
>watts in eddy currents there out of 12kW+ (most of the flux is in the center
>and not the corners/outer edges of the cross-section), as long as the bead
>is thin.
>----- Original Message -----
>From: "Tesla list" <tesla@pupman.com>
>To: <tesla@pupman.com>
>Sent: Thursday, May 18, 2006 1:18 PM
>Subject: Slide choke - second request for advise !!
>
>
> > Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>
> >
> >
> > ----- Original Message -----
> > From: "Tesla list" <tesla@pupman.com>
> > To: <tesla@pupman.com>
> > Sent: Sunday, April 30, 2006 4:04 PM
> > Subject: Slide choke
> >
> >
> >  > Original poster: "MIKE HARDY" <MHARDY@EXECPC.COM>
> >  >
> >
> > I apologise for re-posting this question, but never received an answer > to
> > my real question. (On a side note, DC's invite to investigate this experimentally
> > is very intriuging, lets talk off-list about this further). So
> please > read
> > all of this, including the additional question below. THANKS !!
> >
> >  > A while ago I successfully built a slide choke using a 500 Ft spool
> >  > of #10 thhn house wire, and coated mild steel tig rods, cut to 12". I
> >  > have aquired some "I" laminations that are 1 3/4 inches wide, and 18"
> >  > long. I have enough to make 2 , 1 3/4 square cores. I have about 750
> >  > ft. of #8 PVC wire. Is the length/width ratio of the coil a major
> >  > factor? In other words, can I wind an 18" long coil with the wire I
> >  > have, and just use the laminations as is, or should I wind shorter,
> > and fatter? I'll be using this with  240v, up to 50 A Initially, and maybe 90A later.
> > My second question, is weather I can weld the lamination stack
> >   together at the edges? I see this done with MOT's all the time.