Re: Sync motor(s)

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

In a message dated 8/31/00 4:47:22 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

> Hello All,
>  I'm thinking of converting a small motor of mine to synchronous. However, 
> when
>  I looked inside to determine the size of the flat, I found it to be 
*really*
>  tiny. Look at the diagram at 
>  <http://members.xoom-dot-com/mpn54601/motors_2.gif>http://members.xoom-dot-com/mpn5
>  4601/motors_2.gif
>  There is only one dead pole per side... This is kind of strange because the
>  flats required would only be about 1.5cms across! That's tiny. The motor I
>  would like to use is only 1/15 hp, but that should be good enough.

Michael,

I don't use the dead pole method when I modify my motors,
but it might be OK.  Your armature is probably very small in
diameter, maybe 1.85" or so.  So if 1.5cms is about 1/3rd of
that diameter, that seems reasonable.  I usually make the
flats 1/3rd the diameter of the armature for an 1800 rpm motor
which gets 4 flats.  The 3600 rpm motor gets only two flats.
I've only modified one 3600 rpm motor, and I made the flats
more than 1/2 the diameter of the rotor, but it worked fine
anyway because it's just not that critical to start with.

The flats don't have to be perfectly smooth, but you can easily
smooth them with a file after you're done using the angle grinder.
It makes it easier to measure them and make sure they're the
same sized and distance from each other if their smooth and
regular in size.  If the motor vibrates too much when you're done,
then you know they're not evenly sized or spaced, and that the
motor is unbalanced.  You can balance the rotor by placing
the shaft ends on two razor blades on edge, to see if the rotor
rotates to a heavy spot.  remove some metal from teh heavy
spot until the armature no longer rotates "falls" to the heavy
spot, etc.  It's easy to remove enough material, esp with a small
motor.  Even with the large motor, you can do the job with a large
file which is what I often do.

John Freau


>  Thanks
>  -Michael