Bi-Polar Discussion
updated: 5-22-11
If you are considering a
bi-polar Tesla coil project - first take a close
look at mine (link above), especially the
dimensions and tech specs. Then check out the
links below and any others that you may find. As
far as fit, form, and function goes, I believe
mine is one of the best examples that you will
find. -
John Cooper
Wednesday, February 11, 2009 9:41:55 AM GMT -05:00 Subject: [TCML] Bi-Polar TC
From: jhowson4
Hey Guys I was wondering if i could pick your brains about the bipolar Tesla coil. Specifically what the best way to mount the secondary Like this would be. I am planning on making a small 9kv 30ma coil over the summer
From: D.C. Cox - Subject - Re: [TCML] Bi-Polar TC
The biggest error experimenters make with bi-polars is to make the coeff. of coupling too tight which promotes tracking sparks, commonly called racing sparks.
With a 4" dia. sec coil, the usual distance above horizontal plane of the pri for base of sec is 1.5 inches, which means the two secondary windings have to be separated by approx 3 inches --- with the pri a flat Archimedean spiral. Failure to move each sec outward far enough to set the k value to a reasonable amount (usually 0.1 to 0.14) severely reduces the max sec output spark.
Dr. Resonance
Here is a video of a bi-polar coil in operation. Both high voltage hot outputs are going to round discs about 6" - 10" apart for some nice corona effects - 5-22-11 John C.
http://www.youtube.com/watch?v=YabWJooBCyY
>
The link below is an example of an older era bi-polar coil. It appears to be an antique and is rated at 2kW from a 4kV, 500mA transformer. It uses a .02uF condenser (capacitor). The overall look of this coil is not too good. The ends of the secondary coil appear to be wrapped with black electrical tape as is the primary coil. - 5-22-11 John C.
From: Jeff Behary
Hey All, Here is a new coil based on some ideas from Thomas Stanley Curtis texts.
http://www.electrotherapymuseum.com/2007/TSC/index.htm
A bit strange, but similar to the designs used for early wireless experiments and X-Rays. 6.25" diameter Secondary Coil wound in two sections 10.5" long each on a 24" ABS form. Midpoints are connected together and grounded to Primary Coil. Primary coil is 2" wide copper strap, 1 1/2 turns, 12" diameter. Secondary coils are wound with 18 AWG enameled wire, about 230 turns per section.
Adjustable capacitor was used for tuning, .020 mfd seemed to work best without any dischargers. (This'll be increased to around .024 mfd when the discharge terminals are added). The power transformers are two MOTS wound with primary coils in anti-parallel and secondaries in series with a reactance coil to limit the current from 15 - 20 amps. The spark gap is a 2-series quenched gap, 3/4" diameter tungsten.
Discharge at 18" is pure brush from each terminal, 6-8" long. At 16", sparks will occasionally jump the distance about every 2 or 3 seconds. At 12 - 14" hot discharges occur between the terminals. Jeff Behary c/o The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com
Wednesday, February 11, 2009 9:41:55 AM GMT -05:00 Subject: [TCML] Bi-Polar TC
From: jhowson4
Hey Guys I was wondering if i could pick your brains about the bipolar Tesla coil. Specifically what the best way to mount the secondary Like this would be. I am planning on making a small 9kv 30ma coil over the summer
From: D.C. Cox - Subject - Re: [TCML] Bi-Polar TC
The biggest error experimenters make with bi-polars is to make the coeff. of coupling too tight which promotes tracking sparks, commonly called racing sparks.
With a 4" dia. sec coil, the usual distance above horizontal plane of the pri for base of sec is 1.5 inches, which means the two secondary windings have to be separated by approx 3 inches --- with the pri a flat Archimedean spiral. Failure to move each sec outward far enough to set the k value to a reasonable amount (usually 0.1 to 0.14) severely reduces the max sec output spark.
Dr. Resonance
Here is a video of a bi-polar coil in operation. Both high voltage hot outputs are going to round discs about 6" - 10" apart for some nice corona effects - 5-22-11 John C.
http://www.youtube.com/watch?v=YabWJooBCyY
>
The link below is an example of an older era bi-polar coil. It appears to be an antique and is rated at 2kW from a 4kV, 500mA transformer. It uses a .02uF condenser (capacitor). The overall look of this coil is not too good. The ends of the secondary coil appear to be wrapped with black electrical tape as is the primary coil. - 5-22-11 John C.
From: Jeff Behary
Hey All, Here is a new coil based on some ideas from Thomas Stanley Curtis texts.
http://www.electrotherapymuseum.com/2007/TSC/index.htm
A bit strange, but similar to the designs used for early wireless experiments and X-Rays. 6.25" diameter Secondary Coil wound in two sections 10.5" long each on a 24" ABS form. Midpoints are connected together and grounded to Primary Coil. Primary coil is 2" wide copper strap, 1 1/2 turns, 12" diameter. Secondary coils are wound with 18 AWG enameled wire, about 230 turns per section.
Adjustable capacitor was used for tuning, .020 mfd seemed to work best without any dischargers. (This'll be increased to around .024 mfd when the discharge terminals are added). The power transformers are two MOTS wound with primary coils in anti-parallel and secondaries in series with a reactance coil to limit the current from 15 - 20 amps. The spark gap is a 2-series quenched gap, 3/4" diameter tungsten.
Discharge at 18" is pure brush from each terminal, 6-8" long. At 16", sparks will occasionally jump the distance about every 2 or 3 seconds. At 12 - 14" hot discharges occur between the terminals. Jeff Behary c/o The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com
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