[Russ S.]

I purchased this on CL for almost nothing, yet I'm not really sure what I bought. My hope was that I could use it to create a rotary table for a mill, or perhaps I could use the motor by itself to replace the single-phase turd on my drill press. Unfortunately, I don't know the motor specs (voltage or RPM), and I don't know why it has so many wires. I also don't know why the seller let it go for nothing when he made specific references to how much these cost on eBay. Here are my questions in a simpler format:

1. What type of machine was this likely used on? The owner said he had 3 of these in total, which made me think of XYZ motion.
2. How do I determine the motor RPM and Voltage?
3. Why does it have 3 wires? It spins when you simply hook the red and black wires to a benchtop psu at 12 volts, so I'm assuming it's a brushed DC motor. I don't know what the 3rd wire is then?
4. What's the deal with the 8 smaller wires? Are those simply for the rotary encoder?
5. Why are these so expensive? Do they have super-precision bearings inside? I imagine if those are shot, that would explain the low price on CL.

None of the numbers on the motor match anything on Google btw. I think it must've been a bespoke design for a specific piece of automation equipment.

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[Al_The_Man]

Those motors were originally CMC motors and typically were 24vdc to 48vdc and fitted with a Renco encoder.
If you measure the rpm at 12vdc you could extrapolate the maximum rpm for the typical range of 2000 to 2500 rpm.
The eight wires are the encoder, 6 for A,B,Z and the 3 complement of each plus two for power, usually 5v.
Those are nice gear boxes, BTW, and expensive $$$.
Al..

[Russ S.]

Those motors were originally CMC motors and typically were 24vdc to 48vdc and fitted with a Renco encoder.
If you measure the rpm at 12vdc you could extrapolate the maximum rpm for the typical range of 2000 to 2500 rpm.

Wow, that was a great idea. I used a stopwatch to measure RPM at several low voltages, then plotted in Excel. Setting RPM to 2000 and solving for voltage gave me 90v... which is exactly what the seller told me. I guess I should've believed him. Do you know why the motor has a third (white) wire? Is it a chassis ground or something?

[Al_The_Man]

Not sure of the white wire, but a test to the frame of the motor would confirm it.
If it was thermal cut out there would be two conductors.
Al.

[Russ S.]

Do you think it would be possible to slap a collet chuck on this thing and use it as a mill? For the record, the white wire was indeed grounded to body.

[Al_The_Man]

With the gearhead?
If just the motor, sure, but limited in rpm to ~2krpm.
Al.