Bob Engelhardt wrote:

Is a servo motor simply a DC motor with an encoder or tach? Or is there
something about the motor itself that makes it a "servo motor"?

Thanks,
Bob

That is an interesting question. Most servo motors come as a packaged unit with motor,
encoder, and sometimes tachometer (old days) all together.

I built a few machines to carry a SRIM injection head into presses years ago, I used AB
1326 DC servo motors back then. The constant cycle of starts stops tended to burn the
commutator in a couple spots. So, I took a few apart and cleaned up the commutator to put
them back in order.

There didn't seem to be all that much remarkable about the things other than provision for
a smaller output shaft on the non drive side to stick the encoder and tach on. I'm
speculating that they may be built for short term overloads (starting torque) but that is
a guess.

Someone likely knows more, should be a good thread Bob!

Wes