Motor Woes :(

[Tool-in-the-Box]

Ok, having a problem with this motor on a small bench mill. I flip the switch, there is a flash and a puff of smoke, I inhale, the room starts to spin, then it runs fine. The side has L-R and a bolt with an arrow. The bolt is towards the R but not on it. Should I move it all the way over to R? Is R-L the rotation? I have never seen a motor like this and figured I would ask before doing anything. It looks real old but there is a tag on it so it must have been serviced at some point in its life.

 

[4GSR]

You not going to make it any worst than it is now. That's a older motor that has a brush type face commutator. it's not a DC motor. The "L-R" is the adjustment for the brush holder. I doubt it's out of adjustment, but move it over a little and try it. If its worst, move it back.

Sounds like its about time for a newer motor.

 

[John Hasler]

Ok, having a problem with this motor on a small bench mill. I flip the switch, there is a flash and a puff of smoke, I inhale, the room starts to spin, then it runs fine. The side has L-R and a bolt with an arrow. The bolt is towards the R but not on it. Should I move it all the way over to R? Is R-L the rotation? I have never seen a motor like this and figured I would ask before doing anything. It looks real old but there is a tag on it so it must have been serviced at some point in its life.

I believe that is a repulsion-start induction-run motor. If I'm correct there is a centrifugal mechanism in there that lifts the brushes out of contact when the motor is up to speed so that in can run as an induction motor. Moving the lever to the L position should cause it to start in the other direction. The puff of smoke may just be the brushes lifting off: they and/or the commutator may need servicing.

I'd take it apart and see what's in there. Might be easy to fix. Certainly would be interesting to investigate.

 

[rafe]

I vote for it being servicable. Maybe just a cleaning and brushes .....I love the old motors definately worth repairing most of the time

 

[Mark_f]

It is a repulsion - induction motor. It starts on the brushes and a centrifugal band comes out and shorts the commutator when it is up to speed and it runs as an induction motor. The puff of smoke could be the shorting band sticking or partially sticking. I would clean it or have it done if you don't know anything about them. The lever changes direction , but it has to be in the correct position. These are good motors and if it is running , it is serviceable.It is old , but they are good motors and have plenty of power.


Mark Frazier

 

[Tool-in-the-Box]

Thanks for the info everyone. I will toy with it when I get back to the warehouse. If I can't get it I will have it serviced. It's mounted on a custom bracket attached to a Buke #4 mill. It's an early line shaft model so I have to keep the bracket. The bolt holes don't look standard so swapping the motor out might be a pain. Besides the reversing is kind of neat. I noticed the rpm is 1100 instead of the usual 1725. Does this matter?

 

[Mark_f]

The slower speed is good on the Burke mill. I think the tag says it is 1/3 hp. It is hard to see, But you get the same power no matter the speed. It is just a 6 pole motor instead of a 4 pole.( the number of poles determines the speed. 2 pole = 3600; 4 pole = 1800; 6 pole = 1200 rpm)

 

[Tool-in-the-Box]

Thanks for the info Mark. Yes, it's a 1/3 hp. I have 2 Burke #4's. This is a tiny one with the small table and crank handles. I plan to just have this one running the slotting attachment. The other will be setup for horizontal cutting. I tried mounting the slotter to the other one but it doesn't fit unless I remove the cap over the spindle. I believe the slotter was not in production anymore when they switched to the newer model. Lol, newer being after the line shaft version, 1930ish I guess. -J

 

[hermetic]

I have a motor like this one, albeit a different make. Mine has a large bakelite handwheel for moving the brushgear. It rotates the brushgear round the commutator, which adjusts the speed.I will get slower and slower untill it stops, and then it will restart in the opposite direction and speed will increase again. the post about the shorting bar is very interesting, as I don't know if mine has one or not, but I will be having a look!
Phil.

 

[John Hasler]

I have a motor like this one, albeit a different make. Mine has a large bakelite handwheel for moving the brushgear. It rotates the brushgear round the commutator, which adjusts the speed.I will get slower and slower untill it stops, and then it will restart in the opposite direction and speed will increase again. the post about the shorting bar is very interesting, as I don't know if mine has one or not, but I will be having a look! Phil.

You've got a repulsion-run motor. Those are neat. His is repulsion-start, induction-run and so is not adjustable (except for being reversible).