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Re: Chokes vs Safety Gaps
Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
I may be off topic a bit but I still defend a small RF choke before the RF
signal goes into the NST. Sure the NST has a high inductance and will
supress, but it's like letting the fox into the henhouse and then trying to
deal with him.
A small RF choke in conjuction with some resistors chokes off the high
frequency signals before they get into your xmfr high inductance
winding ---- if you let it get into your NST then it causes tracking and
will damage the delicate HV winding while the inductance is trying to
supress the HF signal. The idea is to grab the bad spikes --- before
entering your xmfr --- not trying to deal with them once they are inside the
NST and serious tracking and capacitive coupling is occuring.
Once they are in the xmfr, as you suggest, sure they are supressed, but
while being suppressed by the large inductance they have to traveling
through the windings first, and, unfortunately this can lead to damage.
Usually in the form of both tracking and capacitive coupling from turn-turn
or layer-layer through the interlayer insulation.
A parallel would be an automotive fuel filter. You try to trap the sediment
BEFORE it enters the carb --- you don't try to clean it up once it's already
inside the carb doing some damage or restricting flow.
We use a small toroid RF choke with 2-4 turns on it before the HF enters the
resistance --- which spoils the Q and further reduces the signal.
Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo WI 53913
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
Sent: Monday, February 09, 2004 8:56 AM
Subject: Chokes vs Safety Gaps
> Original poster: Mark Broker <mbroker-at-thegeekgroup-dot-org>
> I fail to see how a ~1mH choke in series with a ~1kH iron-cored
> secondary will provide any protection whatsoever. If used in conjunction
> with an RC circuit, then that could be bad, too.
> A properly-set safety gap will just barely not fire at full operating
> voltage without the primary capacitor connected, so I fail to see how a
> properly-set safety gap with a properly-tuned and operated TC will be
> ineffective or affect performance.... IME a safety gap will not fire
> unless the TC is out of tune or the power supply is overvolted via an
> overvolting variac.
> My 2 cents.
> Mark Broker
> Chief Engineer, The Geek Group
> On Sun, 08 Feb 2004 21:24:41 -0700, Tesla list <tesla-at-pupman-dot-com> wrote:
> >Original poster: "Gary Weaver" <gary350-at-earthlink-dot-net>
> >If you adjust the safety gap so it won't fire then it doesn't do anything
> >why have it. If you adjust the safety gap so it fires then it takes
> >away from your coil and the discharge sparks get shorter don't want that
> >either. A choke coil provides all the protection needed to protect the
> >transformer from feedback so the safety gaps are a waste of time.
> >Gary Weaver