Re: Motor Sync Problem

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <xanth-at-voyager-dot-net>

John, all,

Comments below...

> It's possible that 3450 rpm motors need wider flats than
> 1800 rpm motors for best results.  I never much trusted the
> dead-pole method of modifying the motors.  I go more by
> the width of the flat.   I don't think the issue of how wide the
> flats should be for a 3450 rpm motor has been much addressed.

I wonder if there is a relationship between apture diameter and
optimum flat width.  If the flats are too thin the motor has
difficulty syncing, too wide and it draws too much current and loses
HP.  There should be an optimum width, correct?  By grinding flats a
little at a time and taking measurements of lock voltage and available
HP, you should be able to determine a relationship.  I could probably
do a study like this if it would be beneficial, just give me some
recommendations.

> I assume you're
> supplying the correct input voltage?   If you happen to have
> a step up type variac (0 - 140V output), it would be interesting
> to see if the motor can be forced to lock at 140 volts, just
> for the heck of it.

Actually, because I had nothing better to do that night, I tried
forcing it to sync.  As I increased above 120v it slowly got closer
and closer to sync but even at 140v it wouldn't.  At what voltage
should a properly milled motor sync?

Thanks again!

Ryan Phillips