Re: sync motor wiring question

["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 3/26/02 10:02:59 AM Eastern Standard Time, tesla-at-pupman-dot-com
writes:


>
> Hi John,
>
> Good to hear you got your motor spinning.   I'm also wondering what the
> Red and Blk wires are for too - I would bet good money they are supposed
> to be used.   But, if the motor is strong enough and not getting too hot
> then who am I to argue with success.   On the other hand, trying to
> figure it out is a fun little puzzle too.



Hi Dave,

I agree the black and red wires are probably meant to be used.  I wonder
if they could be some sort of feedback for some special application?
The last hook up I mentioned in my prior posting gave a pretty
strong torque, but who knows if it was correct?


>
> A couple more you might try if you haven't already
>
> (A) Wht to line
>      Yel, Blk, & Red shorted together to line
>      Cap to Blu and Yel
>
>      or
>
> (B) Wht to line
>      Blu, Blk, & Red shorted together to line
>      Cap to Blu and Yel



Just tried those methods, but the output was weak.  I could
easily stop the motor with finger pressure on the shaft.
Unless this motor is supposed to be super-wimpy, who knows?
I didn't try monitoring the input current, but I guess to mean
anything, it may need to power the rated load anyway.


>
> I'm thinking the Red and Blk windings may be part of the main poles. 



I was thinking that too, but the motor doesn't seem happy with
those wires in use.  I tried some other arrangements yesterday
using those wires also, but they always weaken the motor.  It's
as if they're working against the other windings?

>
> (B) might be the way just since the Yel-Wht winding is about 1/2 the
> resistance of the others making it stand out as the phase shifted
> winding.   You have an 8 pole motor so there's got to be a whole bunch
> of windings.
>
> Did you notice any differences in how long it takes to spin up?  I would
> say the correct connection would spin up in the least amount of time.



Yes, some arrangements spin up slowly.  Others give a feeble torque.
The last arrangement I mentioned in the prior posting gave good torque
and spin up, but who knows if the motor is being over-stressed.  Didn't
get hot, and didn't smell though   :)


>
> I don't think the 3.0uF vs 3.5uF cap will matter at all.  Those caps are
> probably 10% tollerance.



You're correct.  I tried 3.5uF, and saw no difference.  I then tried
4uF, and the motor was even stronger, but ran warmer of course.
3 uF seems good enough.

Funny thing,  I needed a 900 rpm motor for some tube coil
mechanical staccato work a couple years ago, but I didn't suspect
that this motor was 900 rpm.  Even 900 rpm motors can have
Tesla coil applications it seems.  

Some work I'm doing now suggests that 3600 rpm is much
better than 1800 rpm for tiny sync gaps, for certain coils.

Thanks,
John


>
> Good luck,
> Dave Lewis
>
>
>