Re: Motor Sync Problem

["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 9/27/01 10:48:15 AM Eastern Daylight Time, 
tesla-at-pupman-dot-com writes:

> I had two flats milled exactly opposite each
>  other and .750" wide.  After reassembling the motor, I spun it up and to my
>  dismay, it did not sync. 

Ryan,

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.  
Usually 1/3HP, 3450 rpm motors have
larger diameter armatures, but I heard the european motors
have small diameter armatures like that.  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.  When I modified a small 1/10 HP 3450 rpm
motor which had a 1 7/8" dia armature, I made the flats 1 1/16" wide,
but they probably could have been narrower.  It worked well.

John