Question about lathe stalling

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ecdez

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I have a South Bend 11 with what appears to be the original 1/2hp Westinghouse motor wired for 220v. I was taking a cut and it seemed to stall the spindle rather easily so I looked into the flat belt to see if it was slipping and it wasn't so I checked the V belt too and it wasn't slipping either. The electric motor is actually stopping. I pulled the motor and checked the brushes and everything seem fine, oiled it up and rotated by hand and there's no binding so I threw it back in and no change.

I'm no lathe expert but I don't think I should be able to stop the motor by grabbing the lathe chuck by hand. Am I wrong?

This lathe is new to me so not enough experience to see it go from bad to worse.
 
I have a SB 10 inch lathe with a 1/2 hp 3 phase motor. It will take .1 inch depths of cuts in mild steel without slowing down.

Sounds like your motor is buggered
 
There are no brushes in a 220V AC motor.
For a single phase you have capacitors, and some motors have both start and run capacitors.
I suspect your caps are bad. Or you are wired for 110 rather than 220, on a 220 motor.. that would also lead to a weak motor.
 
Can you post a pic of this motor? It sounds like the wrong type of motor to be using if it indeed has brushes
Mark
 
It does indeed have brushes, 4 of them. It's a 110/220 motor and I have it wired for 220 which is how they wired it where I got it from.

I'll post some pics in the morning.

The wiring tag says 1 phase (single phase) and it has 9 wires coming out of it. 6 are paired off and attached to each other for 3 groups of two and the other three go to power. The tag says T1, T2 and T3 are used for forward and reverse but does not show 110 vs 220 wiring.
 
I don't know much about wiring a motor but I've had a similar experience with a motor that would run but had no torque, long story short the problem was wrong wiring for 220v, once corrected, it ran with tons of power, have an electrician look at the way your motor is wired.
 
It probably is a repulsive/inductive motor. They produce high starting torque with much lower inrush current than a capacitor start one. Great motors. From what I understand they were developed for elevators in their day. When the motor comes to speed the brushes lift off the commutator (in most cases) at that time the segments of the commutator are shorted together. If the shorting mechanism isn't working I expect it wouldn't produce much torque.

Greg
 
It probably is a repulsive/inductive motor. They produce high starting torque with much lower inrush current than a capacitor start one. Great motors. From what I understand they were developed for elevators in their day. When the motor comes to speed the brushes lift off the commutator (in most cases) at that time the segments of the commutator are shorted together. If the shorting mechanism isn't working I expect it wouldn't produce much torque.

Greg

Yes, I agree that repulsive motors have 4 brushes and are single phase. I have a 1HP Westinghouse ARS motor in my B&S milling machine. I recently had to make/replace one of the bronze bushings in it because the rotor what hitting the stator. I suggest when you post pictures that you include the motor name plate and any internal pictures you might have, including the wiring. All of these will help everyone get a better idea of how to help you. Brand name and model of motor helps big time!

Ted
 
Here's some pictures. Looks like it is a repulsive/inductive motor. Popped the end cap off and maybe it's me but it appears something is missing.

20171017_081410.jpg20171017_081449.jpg20171017_082150.jpg20171017_082156.jpg


The following pictures are from the Vintage Machinery site.

Mine does not have this on the commutator end of the motor.


40armature.jpg


Mine does have a groove on the shaft, possibly for this snap ring.

3snapring.jpg


It appears my motor is missing this whole assembly :confused:.

8oldspring.jpg



I'm surprised the motor moved at all considering this is what's used to get it going.



All things considered, I did only pay $100 for the lathe so I guess I shouldn't complain too loudly.
 
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Pull that motor and put aside for historical thoughts and get you a new or used 3/4-1 HP 56 frame motor to take its place. May have to make a mounting plate to adapt the newer 56 frame motor to the old, old, frame motor.
 
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