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RE: Motor (sync mod)

Original poster: Henry.Hurrass@xxxxxxx

Thank You,

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Wednesday, April 13, 2005 4:12 PM
To: tesla@xxxxxxxxxx
Subject: Re: Motor (sync mod)

Original poster: FutureT@xxxxxxx

In a message dated 4/13/05 6:30:54 PM Eastern Daylight Time,
tesla@xxxxxxxxxx writes:

>How much do you recommend one should mill off of a typical motor? This >effectively makes this a salient pole motor...sort of. For example, I >am using a 1/2hp, 230V,4-pole,1750 RPM motor which I start at about >280V so it can "Lock-in" and then I reduce the voltage through time >delay to 240V...If I leave the voltage high, the current input exceeds >the nameplate rating and the motor runs excessively hot. What luck has >anyone out there had? Suggestions for milling depth would be helpful, >and appreciated, since I'm getting ready to mill down another armature >or two.


For 1750rpm motors I grind 4 flats that are about 1/4 the armature
diameter.  For example if the armature is 3" dia, I make each flat about
3/4" wide.

For 3450 rpm motors, I grind 2 flats that are about 1/3rd the armature
diameter.  For example a 3" armature would get 1" flats.  Maybe the
flats should still be 3/4" wide like the 1750rpm motor, I don't know.
There are various opinions.

In general milling off more metal makes the motor run hotter.

Some folks use the concept of making the flats match the
width of the "dead poles" of the motor (the poles that have
no windings on them).  However I think this method doesn't always work
that well especially for smaller motors that are 2HP or less.  So I use
the proportional methods described above.

My phase shifter circuit can be used to shift the phase remotely.


John Freau