Old GE Repulsion-Induction motor - reversing rotation?

Hi All,
Not sure if this is the best place for this post - or in the Antique Machinery forum??? Anyway...

I'm on the "home stretch" (or so I thought!) with my Smith & Mills 12" shaper rebuild. I fabbed up a motor bracket recently for an old GE 1 hp single-phase motor that came with the shaper. When I applied power for the first time, it kicked right over with plenty of start up torque. However I checked and discovered that the motor rotation was backwards. So I talked to a few of the motor shops around here and still have one thing left to try today... but was wondering if anyone here would recognize this old style of motor and know how to reverse it's rotation - ie. been there - done that?

Here are some pictures of the ol' gal:



My current thinking is that the halves must be rotated relative to one another as the rear "bell" has the external brush holders in it. The center band is what the motor base bolts into so the two bell halves should be separate from that. One of the motor repair guys was thinking that there may be another set of holes for the 4 bolts just off to the side of the currently used holes... and these would be used to reverse the rotation? The only external leads that are exposed are T1 -> T4 for wiring between 110 and 220 input... these are the old asphalt & cloth sheathed wires... Both the gents at one shop said they had not seen a GE motor that old... so also wondering how old it is??? It has a base that has some machining on one side of it so I was thinking that it was from some other piece of machinery when it was originally purposed...

Any one here been down this road before with one of these old GE R-I motors?

Thanks!
Jeff P

Jeff,
I used to have a Wagner repulsion-induction motor on my old air compressor. They are a great motor with great starting torque! The way that you change the rotation is to adjust the resting position of the brush holder and brushes. (static timing) By moving the brushes around you will change the direction that it takes off in when you apply the juice. This will take a little fiddling to get get it right. Slight adjustments to the "timing" will affect the available starting torque.

On those, you don't change the rotation by switching wires around. All that that does is change the operating voltage.

Have fun with it, they are a great motor when they are right, and you never have a starting capacitor failure.

Frank

Thanks Frank for your input...
The way it was described to me was that I need to rotate the bell through the "neutral plane" to reverse the rotation. One source online mentioned the starting torque was equivalent to a series DC motor (>2x that of a cap start motor) up until the shorting contacts open up (these can be seen inside the back end with cover removed in the last picture) whereby it's similar to a standard induction motor.

Agreed on the wiring - T1 - T4 only reconfigure the run windings for 110 or 220.

Jeff P

KB3AHE said:

Jeff,
I used to have a Wagner repulsion-induction motor on my old air compressor. They are a great motor with great starting torque! The way that you change the rotation is to adjust the resting position of the brush holder and brushes. (static timing) By moving the brushes around you will change the direction that it takes off in when you apply the juice. This will take a little fiddling to get get it right. Slight adjustments to the "timing" will affect the available starting torque.

On those, you don't change the rotation by switching wires around. All that that does is change the operating voltage.

Have fun with it, they are a great motor when they are right, and you never have a starting capacitor failure.

Frank

Click to expand...

X2 on this, I'm sure I've looked at a few Youtube video of this and they showed the motor changing directions.

Repulsion Induction Motor Brush-Shifting - YouTube

http://www.youtube.com/watch?v=ABn_VeFcK4g

RI motors typically have a mechanism built into the brush holders to reverse the motor.
In many cases those adjustments are deliberately easy to reach, from the outside of the
case without undoing anything.

See for example:







The hash marks are visible when the plate at the end of the motor is swung open,
and denote forward and reverse. One lines up the arm that engages the
brush holder with one or the other hash mark.

Your motor may have a similar setup, hidden under the end bell. Basically
you are looking for a way to shift the brush holder on the shaft by about
10 or 15 degrees. You may have to go hunting for this.

Jim,
Looks like yer motor needs a little turning of the commutator and undercutting of the mica. That one looks pretty bad........................

Jeff,
Make sure that your motor winds up fast enough to snap the brushes up off of the commutator. If it doesn't you'll end up with a commutator that looks like Jim's.


Also, be sure you are dealing with a repulsion-induction motor and not a straight repulsion motor. They are usually higher horsepower and the brushes don't snap up off of the commutator. (very old design) They require constant maintenance on the brushes and commutator. The brushes don't last real long in them, but the starting torque is incredible.

Frank

"turning of the commutator and undercutting..."

That's gen-U-wine patina yer looking at there. Clean that
up, you'll reduce it's 'value.' Barn fresh, that's the ticket.

jim rozen said:

"turning of the commutator and undercutting..."

That's gen-U-wine patina yer looking at there. Clean that
up, you'll reduce it's 'value.' Barn fresh, that's the ticket.

Click to expand...

Yer spozed to say that the black shit helps preserve the copper......................

KB3AHE said:

Also, be sure you are dealing with a repulsion-induction motor and not a straight repulsion motor. They are usually higher horsepower and the brushes don't snap up off of the commutator. (very old design) They require constant maintenance on the brushes and commutator. The brushes don't last real long in them, but the starting torque is incredible.

Click to expand...

You can see the brushes inside the motor with the end cover removed in the last picture. The brushes are in a radial configuration on the commutator all connected by a ~10 awg "C" shaped copper wire by the coiled springs you see wrapped around the round brass brush holders... When it spins up one can see some weights move outward from under that silver disk. So I don't believe that these brushes ever move off the surface of the commutator... not sure what type of motor that makes this.

Unfortunately, I had to go play mechanic with my son's truck today so I didn't get a chance to tinker with this today... hoping tomorrow?

Jeff

"One of the motor repair guys was thinking that there may be another set of holes for the 4 bolts just off to the side of the currently used holes... "

The holes will be either thru the middle section (stator) or on the endbell with the brushes.

Be very careful with those old wires, the insulation gets very brittle and falls off if flexed. Meaning replacement of the lead wires will be needed if it is opened up!

Bill