Re: question about driving a DC sync spark gap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "david baehr" <dfb25@xxxxxxxxxxx>


I have used Ol' 12 volt car heater blower motors with sucess, I run a 
full wave bridge and a variac , up to 24volts,...never had a 
problem........................


From:  "Tesla list" <tesla@xxxxxxxxxx>
To:  tesla@xxxxxxxxxx
Subject:  Re: question about driving a DC sync spark gap
Date:  Fri, 13 Oct 2006 11:52:42 -0600
>Original poster: Esondrmn@xxxxxxx
>
>In a message dated 10/11/2006 8:19:28 PM Pacific Daylight Time,
>tesla@xxxxxxxxxx writes:
>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.
>
>I have used a variable speed motor to run an async rotary gap.  It
>was a series wound motor (similar to an old sewing machine motor but
>much larger).  Just connect the field and armature windings in
>series and use a variac - running off AC, no diodes required.
>
>Ed Sonderman
>
>