Re: Induction motor start windings

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Paul,
To add to J.B.'s reply, the two speed winding method makes good sense.
However, I think a start cap is very
probable. I repaired my washing machine a few months ago and I seem to
remember a start cap mounted independant
from the motor. A quick test would be to physically spin the motor shaft by
hand (nothing attached to the
shaft) with power applied. If one direction of hand spinning doesn't work,
try the other direction (these
motors can wired to spin cw or ccw). Be warned, that any time you spin the
motor by hand, the motor can
literally "take off" with a velocity that can be dangerous - use "caution"
so it doesn't take your fingers with
it. If it does start spinning, then the motor probably does need the start cap.

Take care,
Bart



Tesla list wrote:

> Original poster: "J. B. Weazle McCreath by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <weazle-at-hurontel.on.ca>
>
> At 06:48 PM 03/08/01 -0600, you wrote:
> >Original poster: "Paul Arrowsmith
> >
> >A while ago I pulled out the motor from my old washing machine (50Hz 240V in
> >Australia) and now wish to construct a SRSG with it, don't know the HP? but
> >it has a 3.5 inch diameter rotor.
> >It has 3 windings one start and two others joined together
> >The start winding is switched by a centrafugal switch but there is also an
> >extra single pole double throw switch attached to the centrifugal mechanism
> >that switches from one run winding during starting to another run winding
> >when spun up.
> >When I power it up it draws lots of current, hums, and turns slowly if at
> >all.
> >I did not find a capacitor when I salvaged it unless it was mounted out of
> >sight away from the motor. For now I am assuming that a start cap should be
> >in series with the start winding and this is the problem, is this correct?
> >What's with the two run windings? I wonder if it has a different number of
> >poles for running and startup?
> >Hope some one with more motor knowledge than I can help.
> >Thank,
> >Paul A
> >
>
> Hello Paul & coilers,
>
> My father had a motor rewinding business years ago and I asked him
> about your motor.  As it came originally from a washing machine, it
> could very well be a two speed motor, slow for the wash cycle, and
> fast for the spin/rinse cycle.  The slow speed would make use of
> four poles, while the high speed would be two poles.
>
> As to a starting cap, it may or may not have had one.  Generally if
> a motor has a cap, it's mounted to the motor's exterior in a small
> sheet metal can, and the leads pass through a grommet in the casing
> to get inside to the centifugal switch and the start windings.
>
> How many leads, excluding a ground, actually come out of the motor,
> and are they identified in any way?  Here in Canada, there is a more
> or less standard way of identifying the leads.  T1, T2, T3, and T4
> are the run windings, with 1 & 2 being one winding, and 3 & 4 the
> other.  For 120 Volts, 1 & 3 are joined and 2 & 4 are joined, while
> for 240 Volts, 2 & 3 are joined.  A simple parallel or series hookup.
> If it's a single voltage motor, only T1 and T4 will be used, whether
> 120 or 240 Volt.
>
> The start windings are T5 and T8, but in reality only one of them
> actually goes to the start winding directly, while the other goes
> to the centifugal switch (and capacitor) before connecting to the
> other end of the start winding.
>
> I hope I've not gotten you totally confused, but maybe your motor
> will have a similarity that will help you suss it out.
>
> 73, Weazle, VE3EAR/VE3WZL
>
> Listening: 147.030+ and 442.075+
> E-mail:    weazle-at-hurontel.on.ca
>            or ve3ear-at-rac.ca
> Web site:  www.hurontel.on.ca/~weazle