View Full Version : servo II motors from 1989

11-14-2004, 05:54 PM
I have a bridgeport mill from 1975 with servo II power feed moters on all three cranks and am wondering if anyone has experience with these and are they any good. I have not fired anything up as of yet but am cleaning the machine up and getting ready to fire up. Also have one motor that is not installed as of yet not sure why it was removed maybe not working etc. Is it worth fixing these types of motors or did they not really measure up.

11-15-2004, 02:15 AM
You should be able to meter out the coils and make sure that there is no open coils and no shorted coils. If the bearings are good there is not reason that I can think of why it wouldn't be great to use it. How many wires does it have? My guess would be 5 or 6. If a 5 wire then you would probably find one common and one to each of 4 coils. If a 6 wire then you probably have one common for two coils and another common for the other two coils and four coils wires. Each coil should be about the same resistance. There should be no smell indicating a burned out coil. My old steppers work fine. They were built tough. They can be forced to skip a step but on my machine it easily snaps up to 5/8" hardened bits and a drill chuck mount snapped right off when the feedrate was too high. Now I only use a drill chuck for drilling, not milling.

Excuse and disregard the above. I was thinking steppers. Servos use a feedback loop and are different animals.


[This message has been edited by SJorgensen (edited 11-15-2004).]

11-15-2004, 09:01 AM
Servo is a brand name of power feed. They are still in business, and are a very good quality drive. They are worth repairing, but I do not know what cost of repair parts might be. Most machine tool suppliers handle Servo.