Re: Motor Sync Problem

["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 Ryan,

Tesla list wrote:

> Original poster: "Ryan Phillips by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <xanth-at-voyager-dot-net>
>
> List,
>
>     I've been working on making my first SRSG and I'm running into some
> difficulties.  The motor I am using is a brand new Emerson 1/3 H. P. at 3450
> RPM.  It's really very basic, CCW rotation, no start cap, two wires is all
> there is to hook up.  I took it apart and measured the diameter of the
> armature to be 2.810" and the distance between dead poles (or my best guess
> of dead poles) to be .75".  I had two flats milled exactly opposite each
> other and .750" wide.  After reassembling the motor, I spun it up and to my
> dismay, it did not sync.  I've read many discussions on checking for sync so
> I was prepaired.  I made two disks, one cardboard with a single black line,
> and one plexi half black half white.  I used an unrectified supply to power
> about 50 ultrabright LEDS for my strobe.  While the motor is spinning it
> changes tone slightly about every half second.  When using the strobe, the
> black line was very visible but moving slowly CW (about 1-1.5 RPM).  The
> movement also follows the the tones produced by slowing down and speeding up
> as it moves around.  It always slows down in the same spot so I'm guessing
> it trying to lock sync.  It also heats up quite a bit during even short
> runs.  My guess what that the flats were not wide enough and I was going to
> have them milled at 1.0" wide and try it, then 1.25" if that failed.
>
> What do you think my problem is?

It does sound like it's trying to sync. I've modified an 1800 but not a
3450rpm. But I am inclinded
to agree with your assessment at this point. Widing the two widths should
help it sync (the
tradeoff being decreased torque and increased heating). However, best to
listen to as many thoughts
as you can on this one (since you can't easily add material once it's gone)
and make sure you've
checked all the little details (low voltage, friction, etc...).

Take care,
Bart