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Re: SRSG motor anomoly
Coments below,
Tesla List wrote:
> Original Poster: "Bunnykiller" <bigfoo39-at-telocity-dot-com>
>
> Tesla List wrote:
> >
> > Original Poster: "Mark Broker" <broker-at-uwplatt.edu>
> >
> > Hey,
> >
> > I finished machining 4 flats into the armature of a 1725 RPM 1/4 HP (or
> > something close) motor recently. Today, I attached my G-LE rotor (no
> > electrodes yet :-( ) to the motor and fired it up. Ran pretty smooth
> > after balancing. I grabbed an old stroboscope and clocked it at 1800RPM!
> > I was happy, despite there being no way with this scope to test for rotor
> > position vs. the AC cycle.
> >
> > Then, I applied a little load to the rotor by gently pressing on it with my
> > hand. The rotor position rotated about 10 degrees, then a full 90 degrees
> > (to the next pole). It took surprisingly little pressure to cause this. I
> > was wondering if I need to grind a little more off the armature? I
> > machined 4 flats .675" across, which is the distance between the two "dead"
> > poles in the winding. That is according to the directions I found on
> > Terry's site. Is it possible that the motor is crap? It was replaced in a
> > furnace.
> >
> > Thanks
> >
> > Mark B.
>
> Hi mark ....
>
> what HP is the motor rated for ? and what is the diameter of the rotor
> of the motor? I also cut flats into a 1/5 hp motor for "synchronizing"
> but i ended up cutting the flats to .89" wide. the rotor dia was 3.25 "
> and it takes a bit of drag to cause the shift to occur.
I think that it's a 1/4 HP motor, but it could be 1/3.... forgot to look this
afternoon (and I was even working on it!). The armature is somewhere between 3
and 3.5.... my brain isn't working well today.... x-p
> you may need to cut a bit wider flat on the rotor to help maintain a
> locked position....
I made the flats about 5 mils deeper. I didn't take time to measure their
width,
but ttye should be about .75". It worked better, but still took little
pressure
(lightly grabbing the disk with slightly oily fingers) to get the 90degree
shift
to ocurr. The initial 10degree shift was a little smaller, too (~8degress
maybe). I had to go to dinner at that time.... pizza... anyways, I
should get
my electrode hardware tomorrow, so I'll be adding that to the disk, and also
milling a little more off the armature.
Thanks for all your comments. I'll let you know when I get it solved.
Mark B