Re: SRSG phase controller - ATTENTION DAN

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

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

In a message dated 12/13/02 11:45:54 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:

Greg,

Wouldn't the cap value need to be divided by four for 240 volts?
I'm not sure it works that way, just a thought.  In any case,
motors that have a run cap often need a much smaller capacitance
also.  Also, I'm thinking that some of the folks who had a lot of
self-braking may have been able to reduce/eliminate that by
decreasing the cap value.  They may have been getting too much
resonant voltage rise maybe?  In any case it's true that every
situation is different.

John


>It appears as though the uF/HP ratio does not follow a
>linear trend. I tried multiplying John's values for 1/20HP by the
>appropriate amount for 1HP and then divided by two for 240v
>operation. This was far too large, several hundred uF as I recall. I
>actually needed only a few tens of uF for my 1HP, 240v motor, though
>it may be different, as it has discrete start and run caps. With my
>cap size and 10v rise, I get no self braking action whatsoever, at
>any point on the variac's range (found that out by accident) :)
>Again, this may be due to my motor having separate start and run
>caps