Re: Synchronous Motor - How to determine . . .

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 8/16/02 1:44:02 PM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:

I meant not the new electronic high frequency types,  only the
old ballast types work properly.

John


>
> Original poster: "Mccauley, Daniel H by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
>
>
>
> I'm just curious, if not an electric flourescent light, what would you
> use???
>
> Thanks
> Dan
>
>
>
> Dan,
>
> The quickest way is to place a piece of white or black tape across
> the rotor, and observe the spinning disc under ordinary flourescent
> light (not electronic fluorescent).  If the motor is locked in sync 
> properly, the faint blurred pattern will not rotate.  You can unplug
> the motor and then the pattern will rotate as the motor spins down.
> Just before the motor locks into sync as you raise the voltage,
> a hunting (unsteady) sound may be heard.  The sound will
> suddenly become very steady as the motor locks into sync.
> Some folks use a neon bulb and build a circuit to act as a strobe
> to see if the disc is synched, but I just use the fluorescent light
> method which works well.  Some folks have trouble seeing the
> pattern until you gain experience viewing it.  
>
> Sometimes if the motor can't quite lock with the rotor installed,
> the use of a larger than normal run capacitor will help it to lock
> (assuming the motor uses a run capacitor).  Another way to
> assist the lock-up is to power the motor from a 140 volt variac,
> or a step-up transformer which outputs 140 volts.
>
> John
>
>
> >
> > I have my synchronous motor with the rotor set-up.  How am I able to tell
> if
> > my motor is running at the correct speed and that the rotational weight of
> > my rotor is not slowing the motor down.  Any easy way to determine this?
> I
> > don't have access to any type of motor tachometer whether it be a physical
> > connect one or ones that use a light beam and a piece of tape on the
> shaft.
> >
> > Thanks
> > Dan
> >
> >
> >
>
>
>
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>