RE: question about driving a DC sync spark gap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Aron Koscho" <kc5uto@xxxxxx>

Is the power cabled to the motor shielded? If it is not this could be
the cause of your problem. I have run DC RSGs before and had similar
failures with out shielded cable. Now all my RSGs are feed with power
through MC cable that is grounded at the TC base.

Aron

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Wednesday, October 11, 2006 11:08 PM
To: tesla@xxxxxxxxxx
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.

Background:. This is an 11" OD coil 57" tall #18 wire, 15kva pig, 11 to
15
foot arcs.