RE: question about driving a DC sync spark gap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Why not make a cheap bridge out of cheap 1N4007 diodes. Paralleling should
do it 30 amps surge, 1 amp forward all day. 1000v PIV. Cheap. S&JY gave me
the idea awhile ago. Works great for lots of stuff. How many amps is you
motor? Double it for startup. Ramp it up slow.
Jim Mora

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Tuesday, October 17, 2006 7:10 AM
To: tesla@xxxxxxxxxx
Subject: RE: question about driving a DC sync spark gap

Original poster: "Leigh Copp" <Leigh.Copp@xxxxxxxxxxx>

Steve,

What is the reverse voltage rating of your bridge?

Leigh

	-----Original Message-----
	From: Tesla list [mailto:tesla@xxxxxxxxxx]
	Sent: Tue 17/10/2006 1:15 AM
	To: tesla@xxxxxxxxxx
	Cc:
	Subject: Re: question about driving a DC sync spark gap
	
	

	Original poster: "S&JY" <youngsters@xxxxxxxxxxxxxxx>
	
	Miles,
	
	I also use a DC motor with my async RSG.  I have had no problems
with the
	bridge rectifier, which is only rated for about 10 amps.  I think
perhaps
	the secret is to mount your bridge rectifier and filter cap adjacent
to the
	motor so that connecting wires are only a few inches long and cannot
pick up
	any significant RF or other nasty impulses.  Then feed AC from your
variac
	to your rectifier/filter/motor through your 10 or 20 ft power cable.
	
	So far, with six foot streamers flying around, this works fine
without any
	filtering of the AC power cable.
	--Steve Y.
	
	> ----- Original Message -----
	> From: "Tesla list" <tesla@xxxxxxxxxx>
	> To: <tesla@xxxxxxxxxx>
	> Sent: Wednesday, October 11, 2006 11:08 PM
	> Subject: question about driving a DC sync spark gap
	>
	>
	>  > Original poster: "miles waldron" <mileswaldron@xxxxxxxxxxx>
	>  >
	>  > Dear All,
	>  >
	>  > Is anyone using a DC motor to drive an async rotary spark gap?
If
	anyone
	> is
	>  > doing this, how is your variable DC power supply built? We are
having
	>  > consistent CATESTROPHIC failure of the power supply diodes. Not
the
	motor.
	>  > The motor is always fine, and the variac is always fine. We are
using
	huge
	>  > giant diodes (300V @400A) and they are frying instantly. We
have tried
	>  > chokes in series, caps in parallel, caps in series, but nothing
seems
	to
	>  > help.
	>  >
	>  > Please help before we shoot the DC motor with a 1000 watt CO2
laser,
	and
	>  > rebuild our spark gap using a variable AC motor.