Help with a Kimble motor needed

I just purchased this older style kimble variable speed motor to run a 8x12 Golding Jobber. I figured it would need a service, so I took it to my local electric motor shop. They seem, however to have basically no idea about what it is or how to work on it, and I will admit that I too know next to nothing about electric motors.

They’ve quoted me what I feel is an obscene amount to “clean the brushes”, but when I asked them about how the speed was adjusted on the motor (as I thought it was via the brushes somehow?) they told me that I needed to buy a separate $350 speed controller. I know this is wrong. Can anyone look at these pictures, or post pictures of their motor, and explain how the speed is controlled?

BTW, they also told me this was a three phase, non-variable speed motor even though the plate clearly says differently.

Thanks in advance - I feel like this motor would work fine if I had a little more knowledge about it.

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Speed is controlled mechanically through the lever on the back of the press. There is part of the linkage shown in the photographs. You should be able to move this lever back and forth… it will control the speed of the motor as well as reverse rotational direction.

Wire it up to a standard switch and see how it runs. You shouldn’t need anything extra unless you want the remainder of the linkage that would allow you to control the speed from the front of the press.

Hope this helps,

For 350 you could get a new motor so I wouldn’t listen to them on at. Did the seller show the motor running or tell you it worked?

Brad, can you explain how to get the switch hooked up to a drive motor like this? Is it different for every motor? I asked a question about it but it seems you might understand this.

A few possible avenues re older style motors, in single phase form, yes they were controlled via the brushes but only by retarding the brushes in relation to the commutator and consequently pulling masses of current when slowed down as did my Thompson Platen, re juice EXPENSIVE? Most three phase equipped letterpress machines were (motorwise) speed controlled via banks of resistors, which frequently burnt out when the machine was in sustained slower speed mode. Re mechanical speed control (with no reference to electrical interface) usually implies the need for coned pulley to give speed variation which also normally involves the need for the motor to describe a small arc around its mounting shaft. Switch gear? single phase would usually be reasonably sturdy metal orientated (not plastic) DOUBLE pole unit, to make/break contact with live and neutral at once. Three phase on/off is usually via the appropriate 3 phase contactor, which itself is operated by one phase, as a tiny loop within the switch itself. Normally these type of switches incorporate a very protruding stop button (RED) for emergency use, like just BEFORE you make structural modifications!!! to your fingers or worse?

The “brush rigging” ie. the part of the motor that holds the brushes, rotates to the left and right. Try it (with the power disconnected) and you’ll see how it works. It varies the ‘neutral plane’. This is how the speed is contolled. Rarely doens anything go wrong with these motors. I have a number of them and the worst of them look like junk and they still run. You should be able to see where the linkage arm connects to the brush rigging. Play with it under power but not belted to the press. You’ll see how it works. By shifting the brushes past the ‘neutral point’ the motor will run in the opposite direction as well. Make sure you keep the RPM within the range stamped on the nameplate - especially do not exceed the high limit as they will scream and possibly self destruct from centrifugal force.