Re: John Freau's SRSG motor controller question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 5/30/03 2:45:59 PM Eastern Daylight Time, 
tesla-at-pupman-dot-com writes:

Terry,

Possibly the system may resonate and draw heavy currents when
started with the variac not in the minimum inductance position.  The
amount of this resonance may depend on the capacitor value.  In my
tests, the motor did not seem "happy" starting at certain random
positions.  For this reason I always start the motor with the variac
at minimum inductance or near to minimum.  Others may have seen
different results, I don't know.  Regarding the 45A peak currents, I guess
this would depend on how long such currents continue.  Variacs can
take a lot of abuse as long as they don't get too hot and the brushes
do not arc.  Using the smallest possible capacitor value which still
gives a full phase range, is probably a good idea.

John


>Hi,
>
>I am working on a dwell controller of the John Freau design and I was
>wondering if there is any problem with starting the motor with the variac
>in any random position?  I think I heard that it should be started with the
>variac in the minimum inductance stetting.
>
>Also, does the say 45 amp peak starting current hurt the variac?
>
>http://hot-streamer-dot-com/temp/030513-03.gif
>
>Cheers,
>
>   Terry
>