hysterisis motors (also selecting sync motors, and phase shift question) (fwd)

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Original poster: "william_b_noble" <william_b_noble-at-email.msn-dot-com> 

I believe, but have not proven, that if you were to magnetize the armature
you would get lock in at the same position.  Depending on the material, you
may be able to permanently magnatize the material itself, you you may have
to drill a hole, epoxy in a permanent magnet or two and drill some balance
holes - The theory is that if there is a prevailing magnetic field, that is
how it will "want" to lock in phase.  This might also work on regular
induction motors.   Note please this is a hypothesis, not a tested theory,
so it may not work (but it seems reasonable enough).  If it works, it is
surely a lot easier to drill a hole and glue in a couple of PM magnets than
to file flats on an armature, and you will lose a lot less torque too.
Bill
www.home.labridge-dot-com/~wnoble
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-poodle.pupman-dot-com>
Sent: Wednesday, December 06, 2000 6:50 AM
Subject: Re: Bulk Buy Toroids (also selecting sync motors, and phase shift
question) (fwd)


-----snip
> Avoid the hysteresis motors like the ebola virus!!  They are NG for
> our use.  I had tested one in the past, and I thought it locked
> in the same position all the time, but I retested it, and it does not.
> Fortunately, these motors usually are marked as hysteresis types.
> The armature is a special metal that has a large hysteresis
> characteristic, and so it can lock in any random position.  If you
> use this type of motor, you'll have to re-adjust the sync phase
> every time you run the coil... not fun at all.  I wonder if grinding
> flats on these motors would make them lock in the same position,
> I wonder if anyone has tried that?  Somehow I suspect it won't
> work well.  My hysteresis motor required the use of an 8uF capacitor,
> and I was surprised that it worked poorly with a 15uF cap, I don't
> know if the cap size is critical on all hysteresis sync motors.

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