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Re: Magnifiers revisited





---------- Forwarded message ----------
Date: Tue, 7 Oct 1997 11:30:59 -0500
From: "DR.RESONANCE" <DR.RESONANCE-at-next-wave-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Magnifiers revisited 

To: Tesla List

You can turn almost any Tesla coil into a magnifier as follows:

Assume you a normal Tesla coil running at 3-5 kw of power.  Remove the
secondary coil from its normal position and place it on an insulated
platform a few feet away from the normal primary coil.  We placed one of
ours in a test on a large porcelein insulator.  Now connect a piece of
heavy welding cable (very fine strand) such as 2 ought directly to the
bottom of the secondary coil where the ground would normally attach.  We
also attached a 2 inch dia ball to help prevent corona in this area. 
Attach the other end of the welding cable to the same point where the
primary tap is presently attached (next to it is fine).  Turn on your
system and run it --- viola!! --- you now have a magnifier system that will
give sparks equal to or slightly longer than your normally running coil
system.  Adjust the 2nd tap point slightly as necessary.  You can also
adjust the primary tap but usually this is not necessary.  Although a
faster quench helps out it seems this technique works quite effectively
with almost any coil design and usually works right out of the gate without
too much adjustment.  Yesssirrr --- I can almost see everyone running for
the garage right now!  It works and its unique.  You can even mount your
primary and tap into a large "hidden" box with only one very large
insulated wire coming out and running to the bottom of the displaced
secondary coil.  Most electrical people scratch their head for awhile as
most have never seen a transformer work without a coupled primary in the
vicinity of the secondary coil.

DR.RESONANCE-at-next-wave-dot-net


----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Magnifiers revisited 
> Date: Tuesday,October 07,1997 9:32 AM
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Tue, 7 Oct 1997 10:01:28 -0400 (EDT)
> From: FutureT-at-aol-dot-com
> To: tesla-at-pupman-dot-com
> Subject: Magnifiers revisited
> 
> All,
> 
> I've built a few magnifiers over the years, one of which gave an 80" 
> spark.  Whenever I want to explore some aspect of a magnifier, I 
> toss one together and do some tests.  Perhaps this data will help
> those who are just entering the magnifier arena.
> 
> Today, I decided to convert my 42" spark classic TC into a magnifier
> to observe the quenching and overall performance.  This was 
> accomplished quite easily by using an old 6 1/2" by 6" tall secondary
> for the driver secondary (#28 magnet wire), and using the original tall
> secondary as the new magnifier extra coil.  The remainder of the coil
> remained exactly the same; .007uf cap, 8 point series quench rotary,
> 120 BPS synchronous, 5" by 20" toroid, etc.
> 
> At first the driver was loosely coupled at .29, the pri. tap was moved
> out by 2 turns, and the coil was run.  Sparks hit 40", and hit 44" one
> time.  Sparks also reached 44" on occasion in the classic TC.  The
> magnifier sparks however appeared to be less bolt-like, and appeared 
> more plasma-like.  Instead of hitting the measuring wire with a snap,
> they seemed to hit with a wispy sizzle.  Overall, the coil was weaker, 
> and the average sparks were shorter.
> 
> Next I gradually increased the coupling to k = .39, but the sparks
> weakened as the coupling was increased.  The sparks appeared
> sluggish and dull -- the classic signs of poor quenching.  Just to
> be sure that the 12kV, 30ma tranny was still ok, I loosened the
> coupling back to k = .29, and the sparks increased in length.  If I
> tried to increase the coupling beyond k = .39, problems with arc-
> over occured since this coil was not originally designed as a 
> magnifier and a saucer primary is being used.
> 
> Observing the quenching using a solid state scope, I saw that at
> k = .29 the quench occured at the 2nd notch, and at k = .39 the 
> quench occured at the 3rd notch.
> 
> BTW, the driver secondary L = 20mH, and the extra coil L = 100mH.
> The primary has 42 turns and is tapped at 35 turns as a magnifier
> and at 33 turns as a classic TC.  Input power was 740 watts in each
> test.
> 
> Conclusions and speculations:
> 
> 1) This series quenching rotary does not quench well enough for a 
> small magnifier (toroid sized for max spark length) at 120 BPS. 
> It is possible that a higher break-rate would create a 
> larger ionized load around the toroid and promote 
> better quenching but I did not try this.  I suspect that any benefits
> would be marginal at best.  This series quenching rotary is barely
> adequate for a small classic TC and quenches anywhere from 1st
> to 3rd notch.  Perhaps the rotary could be improved by using a
> larger diameter rotor, adding air cooling, etc.
> 
> 2)  As I tightened the coupling, the quench degraded and the sparks
> weakened.  A magnifier probably requires multiple heavy streamers
> to promote good quenching.  If I had cranked up the power, the
> quench may have improved and the spark may have lengthened,
> but I would have obtained a decreased "efficiency" as measured by
> power input vs. spark length.  
> 
> 3)  The relatively low frequency used did not solve the quench 
> problem, however low frequency operation is theoretically a plus.  
> 
> 4)  The greatest hurdle blocking the success of small magnifiers
> is the attainment of adequate quenching.  Anyone contemplating
> the construction of a small magnifier should be prepared to deal 
> with the above issues.  In general, quenching is assisted by spark
> loading, so the larger the output sparks, and the greater the
> number of steamers, the better the quenching will be -- the gap
> can only do so much.  In large magnifiers, the heavy spark loading
> probably helps the quenching, but other types of problems move to
> to forefront.
> 
> John Freau