Re: Fwd: [jlnlabs] TESLA COIL REVISED

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Christoph Bohr <cb-at-luebke-lands.de> 

Hello All, Hello Jaro.

I wondered about this fact, too. Some weeks ago I read "man out of time" and I
remember a quote from tesla where he states that "hundreds of turns on the
secondary circuit are not neccessary". But on the other hand he only uses 2
turns as primary, this leads to a reasonable L1 L2 inductance ratio that
translates into voltage gain if I understand this right.
Would be an interesting thing to try, I thought about building a replica of
the big flat coil Tesla used in his Houston Street mabe in an smaller scale
ofaround 2 feet. But currently I am working on other projekts so this will be
delayed until 3rd quarter of 2004. On the other hand this should not be too
much work just for a "proof of concept"-coil

Sincerely

Christoph Bohr

 >Am Dienstag, 30. Dezember 2003 19:01 schrieb Tesla list:
 > Original poster: Tom Stathes <newphreak_16-at-yahoo-dot-com>
 >
 >
 > Note: forwarded message attached.
 >
 >
 > __________________________________
 > Date: Sat, 27 Dec 2003 06:54:13 -0800
 > Subject: [jlnlabs] TESLA COIL REVISED
 > Reply-To: jlnlabs-at-yahoogroups-dot-com
 > Content-Type: multipart/alternative;
 >   boundary="7sXqLKCsjnyYoY64pxfTPFI2R0ZhKSZJleFSmA1"
 > Content-Length: 1751
 >
 > I have a problem with today's Tesla coils. The way they're built these
 > days, is with the secondary made with SEVERAL HUNDRED turns of thin
 > wire, which is WRONG. When Nikola Tesla made his coils, they only had
 > 50 to 100 turns of a THICK wire as the secondary.
 >
 > The problem with hundreds of turns of a thin wire is that they have
 > many times bigger resistance than Tesla's original coils. This big
 > resistance increases losses, and so minimizes voltage increase due to
 > resonance. Thick secondary wire will have small losses which allows the
 > resonance to build higher voltages.
 >
 > Here's how Tesla's Colorado Springs coil was built. Primary were 2
 > turns of a thick cable, and secondary 100 turns of No. 8 wire with a
 > diameter of 51 feet. That's 1:50 ratio between primary and secondary.
 > Input was 50 kV into a .004 mF capacitor which was connected to the
 > primary coil through a spark gap. It could resonate at frequencies from
 > 45 to 150kHz.
 >
 > Tesla's power-transmission coil patent shows almost the same coil,
 > except that the diameter was 8 feet, and secondary was wound as a flat
 > coil (also no. 8 wire), and resonance was around 250kHz, producing 2 to
 > 4 million volts.
 >
 > So if Tesla's coil could be reduced from 51' diam. to 8' diam., while
 > keeping the 1:50 primary/secondary ratio, then it should be no problem
 > to reduce that coil further to about 1' diameter, using only 50 turns
 > of a thick wire as a secondary.
 >
 > The only problem would be the 50kV input that Tesla used, but even
 > using only 5kV from a neon transformer should produce 200 to 400kV
 > using the 1:50 ratio, since 50kV input produced 2-4 million volts.
 >
 > Also, using a 1' diam. secondary will reduce its inductance, which
 > will increase resonant frequency to several MHz. And using a very thick
 > wire, copper pipe or Litz wire would be needed to reduce high frequency
 > losses.
 >
 > So, using a 1-turn primary and 50-turn secondary on a 1-foot diameter
 > air-core, should make a TRUE Tesla coil which will have lower losses
 > and more powerful resonance than today's "Tesla coils". Plus that makes
 > it much easier to make than winding hundreds of turns.
 >
 > Jaro