Re: SRSG motor modification

[FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 8/6/00 2:46:20 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

> Original poster: "Garth van Sittert" <garth-at-mediasupplies.co.za> 
>  
>  I recently modified a 1/4 HP capacitor start; approx. 2800 rpm motor to 
make 
> it
>  synchronous.  I ground two flats across the 'dead poles' on the armature
>  according to motor1.gif etc...  However I must have done something wrong 
as 
> it
>  is not synchronous.  Using a neon as a timing light the blur only comes 
into
>  focus a couple of seconds after power off when it is coasting down.
>   
>  The motor only has 16 poles so I was't 100% sure on the modification 
> compared
>  to the instructions referenced above which I have seen mentioned a couple 
of
>  times before on this list.  The starter windings seemed to ocupy much more 
> pole
>  space than the ones shown in the diagrams and are interwoven with run 
> windings
>  as well, so I thought rather than grind too much..... 

Garth,

I dont' use the concept of the dead poles when I modify my motors.
Rather I go by proportion.  For a 1 7/8" dia armature, I made my
poles 1 1/16" wide.  But they could have probably been less wide.

A motor of your speed, if it will go to 3600 rpm when modified
should have just 2 poles.  If you're looking at the slots which hold
the wires in the stator..... these are not actually poles.  I'm just
curious, what was your armature diameter, and how wide did you
make the flats?

I assume you put some sort of cardboard disc onto the motor
shaft and drew a black line across it to observed it with the
neon light?  In any case this is what I do, but I use a fluorescent
lamp.  

John Freau