Speed control for kluge needed

The modern replacement would be a VFD. Variable Frequency Drive. They are becoming more affordable all the time. As long as your motor is healthy. A better pic of the motor plate would help a lot.

I put a better picture of the motor and the information plate. , it’s still in great shape

I still can’t read the motor class (far upper left on the motor nameplate), which is the most important piece of information for deciding what type of speed controller will work. The motor evidently has a wound rotor and brushes. Kimble’s 1903 patent No. 733,401 for a speed control for this type of motor shows the field coil connected directly across the line. Also connected across the line is the primary of a transformer. The transformer secondary, which has multiple taps, powers the armature. Motor speed is then roughly proportional to armature voltage and independent of frequency. The motor class designation will tell us whether this is a repulsion motor as I have just described, or a repulsion start, induction run motor, for which a VFD might work.

In checking with a local motor expert, this motor is probably way too old to work with a VFD. Apparently VFD’s input to the motor a “Corona” current or carrier voltage? Either way, he said this motor likely does not have proper winding structure or materials to handle this. It would “probably work, just not very long”. If production and dependability are priority, then a new motor and VFD would work. If period correctness is priority, well, got to get the old stuff fixed.

Kimble made several different kinds of commutator motors, including compensated repulsion and series wound motors.

I thought I had a reference that would decode that motor class, but I have searched and failed to turn it up. There is lots of info available on GE equipment, but Kimble documentation is hard to come by.

I have a series-wound Kimble Class AR motor dating from about the 1920s, in which speed and direction are both adjustable by shifting the brushes. I haven’t wired it up to run it since acquiring it last winter. I believe Kimble used the brush shifting method in motors up to about 3/4 HP and some sort of armature control on larger motors. The other two Kimble motors I have used also are adjustable by shifting the brushes.

If you haven’t already done so, you could check for continuity between the field windings and the brushes, either by inspecting the connections or by measuring with a multimeter.

If you own that controller shown in your original post, you may find a wiring diagram inside if you can figure out how to open it up. Past Briar Press posts have indicated that a controller that looks just about identical to yours was manufactured by Cutler-Hammer (but with a Kimble nameplate on the outside), and worked by using an autotransformer to vary the voltage supplied to the motor. I have a wiring diagram for this controller. I can’t guarantee that it is applicable to your motor. If you want to use this kind of controller but your autotransformer is burnt out, you could get a new autotransformer with the right specifications and mount it in your old box. Unlike rheostats, autotransformers are quite efficient.