Grant Erwin wrote:

I do *not* like leaving the larger start cap in the circuit. It usually
will
buzz loudly. I had a buddy with a phase converter set up like that and it
was awful to work around. Finally I introduced him to Bob Powell who
reworked
his converter to take the start cap out of the circuit (don't know how, but
knowing Bob, it was most likely a potential relay) and now it's nice and
quiet.
In my experience potential relays are extremely robust and work just fine.
Well thats an option. I was hopeing to 'simplify and add more lightness'
but we are willing to go for seperate start and run caps if we have to.


Your start capacitor needs to be big enough to reliably start the motor
while
small enough so that too much current doesn't flow for your wiring. Bigger
means more current means faster starting for more initial cost. Smaller
means
slower starting with less current for less money. Start caps can be
electrolytic
and are thus cheap.

But not if they behave as disposable or even one-shot items :-) I think
the problem is duty cycle related, if it cycles to often, pop goes tha
cap. I was planning on caps rated for continuous duty and compromise a
bit on starting torque.

Run caps should be oil-filled and cost much more,
but for
a 1.5kw motor shouldn't cost that much. I can go look up recommended start
capacitance per horsepower but so can you. If you don't like the new Google
groups try groups.google.com.au - the Aussies still have a good google
going
down there.

Gooogle groups here is still good.

Thanks for yoyr assistance.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
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