Re: Armature flats and strobe lights, to do with making a motorsynchronous

["Finn Hammer" <f-hammer-at-xxxxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Alan!

There one good way that I know of, that will tell you if the motor is
getting in sync. I use it every time I start the rotary!

Connect an analogue amperemeter in series with the motor, and ramp it up
with a variac. If you do this in the unmodified state, the current will
simply rise with voltage in a smooth, if not linear fasion.
As soon as you start to remove material from appropriate places on the
rotor, this changes. When you ramp the voltage up, the motor acts as
before, up to a point, then the current starts to pendle btwn. "much
more" and the usual. As you ramp it up higher, the frequency of this
pendling increases, untill it suddenly stops: the motor is in sync. You
can hear it from the sound too, and I swear, once you have heard it, you
will feel that you "own" the behaviour of the modified motor in your
guts. After you have heard it once, you will not need instruments to
tell if the motor lochs in sync anymore :-)
It sounds like it is hard, but it is not. Just go ahead and do it, then
you`l know.

Cheers, Finn Hammer

For a nice gap, take a look at:

http://home5.inet.tele.dk/f-hammer/tesla/tesla.htm

Tesla list wrote:
> 
> Original poster: "Kelly & Phillipa Williams" <kellyw-at-ihug.co.nz>
> 
> Hi ,
> 
> I have continued playing with our old washing machine motor with the object
> of making it synchronous.
> It is currently in it's unmodified condition. When we make a dot with twink
> on the rotor, and turn it on, we see a yucky blur under fluorescent light.
> It seems my fluorescent light is not working too well as a strobe light at
> 50 Hz - it's a *really* old crappy light salvaged from an office that was
> throwing it away.
> I thought the motor, even though it is unmodified (still 'slipping') would
> still be running close enough to 50 Hz
> (unloaded) for you to see the twink dot, even if it moves relative to the
> case.
> Q> is the motor not close enough to 50Hz to see the dot, or is our
> flourescent light not working properly?
> 
> In a search for new ideas, I thought we might use the 555 ignition coil
> driver circuit for getting continuous arcs / sparks, but modify the 555
> frequency to get 50 Hz, run it through the ignition coil, and attach a xenon
> flashtube (used for spark timing in cars).  This should give us the 50 Hz
> necessary (mains frequency in NZ).  The only thing I'm not sure of is the
> duty cycle.  Does it really matter?  Can I just use a 50% duty cycle, or
> just match it to whatever works with the xenon tube?
> 
> I have an angle grinder and all the accessories, I thought that once I know
> how to get a strobe light I will start grinding flats (2) on the armature, a
> tiny bit at a time, and then recheck it against the strobe light, till the
> twink dot stays at the same place relative to the case of the motor.
> 
> The motor is a 12 pole / 2 pole multispeed motor, I would use the 2 pole
> speed, would that give an RPM
> of 3000? (50Hz)
> 
> Is this all on the right track, or am I wildly off course here?
> 
> Thank you,
> 
> Alan Williams