Re: Synchronous AC motors...

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

Original poster: FutureT-at-aol-dot-com 

In a message dated 1/26/04 5:57:15 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:

>Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com>
>
>How do I tell if I have a synchronous AC motor? It has a 4 coils wound onto
>some transformer laminate that surrounds a shaft which is nothing but a
>steel rod with some circular transformer laminate on it. Is this a
>synchronous motor and if so is 1/6 HP at 1550 RPM enough? How do I position
>the disk with electrodes to make sure it fires at the top of the cycle
>etc?Thanks.


Hydro?,

A 1550 rpm motor is not synchronous.  Usually 4 pole async
induction motors run at 1725 or 1750 rpm.  A real synchronous
motor will run at 1800 or 3600 rpm on 60Hz power, and will run
at 1500 or 3000 rpm on 50 Hz power.  An Induction motor can
be modified by filing or grinding flats onto the armature to make
it synchronous.  Generally 1/6HP is pretty good for a rotary
provided the rotor is not too heavy.  For example I used a
1/20HP motor to power a 6.5" dia x 3/8" thick G10 rotor
at 3600 rpm using a true sync motor.  If you modify an async
motor to make it sync, then you lose some power in the
process.  If the motor uses a run cap or start cap, then it
can drive a heavier load usually.  Often the size and weight
of the motor can give clues to its real torque capabilities.

When you do actually have a sync motor, the electrode phase
alignment is best determined by trial and error by rotating
the motor as needed in its cradle, or by using my electronic
phase shifter, or in some other way.

   <http://hometown.aol-dot-com/futuret/page3.html>http://hometown.aol-dot-com/futuret/page3.html

In another posting today, I explained how to determine if a motor
is running in sync with the AC power.

John