Re: [jlnlabs] TESLA COIL REVISED

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


Using several hundred turns of thin wire is the best way to construct
classic Tesla coils.  We use 1000 to 1,400 turns on most all of our coils.
Tesla's coils were mostly magnifier designs and in these designs hi-Q factor
for the "driver" coil is essential while the "resonator" coil does not
require hi-Q for maximum output.

You need to balance the Q factor against the load impedance and topload
capacitance and consider all three to determine best output parameters.

1,000 to 1,400 turns of wire works great with a large secondary toroid
usually 2 x the sec. coilform dia or more.  This design produces optimum
output from classic coil designs.

The large number of turns produces a high inductance ratio which is critical
to achieving best output.  Q factor does not enter the equation for classic
coil design but is very important in magnifier design such as Tesla was
using on his Col. Springs coils.

Output (gain) = Einput x sqr (Ls/Lp)        (classic coil)

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
 > First you present a different idea and then labeled all the working
 > coils as "Wrong". Have you tested your ideas and proven they work as you
 > expect? If so we'd all like to see the results as it could open up a new
 > area of coiling.
 >
 > Regards,
 > Brian B (trying to keep an open mind)
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: Tuesday, December 30, 2003 10:01 AM
 > To: tesla-at-pupman-dot-com
 > Subject: Fwd: [jlnlabs] TESLA COIL REVISED
 >
 > 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
 >
 >
 >