Bridgeport servo motors?

We have a 60s era Bridgeport LINE-A-MILL, it has a optical tracing unit and a huge cabinet containing the old style electronics, the servo motors are rather massive units with built in handwheels, dont know alot about it but all electronics are manufactured by Stewart-Warner, the servo motors are DC brush type with tachometer feedback and have a 5 pin connector, could these servos conceivably be utilized into a updated cnc system?

you should replace all the servos and motors, old motors pull lots of amps and can burn up new drivers fast

If you're going cheap and the motors and drives work, why remove them, if the drives are shot get new ones that are big enough to drive those servo motors, if the motors need brushes or a once over it may be cheaper/easyr than trying to fit new motors and making all the asorted mounting brakets to drive your machine.and then again it may not.
then you have to consider what are you going to use for position feedback.

Thank you for the replies. I haven't even looked into replacement motors, I doubt the're available and if so, certainly would be breathtakingly expensive, these units combine the motor, handwheels, bearings, etc. in a sealed unit. It's not that the drive is shot, but that it is a optical tracing system, not cnc. So my question is: whats the chance of a homeshop type cnc system driving these motors? I imagine the tach feedback is an analog signal and I would assume the voltage, current demands of these motors are higher than modern servo motors, could some arrangement of A/D converters and amplifiers make this work? or am I just hoping for too much with this old a system? If not it does function fine as a manual mill.

Dear Sir:
Do you have schematics or a manual for your machine? It would be helpful to know what voltage the motors use. One could just measure the power supply voltage, I suppose.
Gecko Systems makes an economical DC servoamp which you might use as a replacement if one is needed. Does the machine have ballscrews? These are desireable for a CNC. There are several drop-in replacement ballscrews made for Bridgeports. As you probably know, there are several PC based CNC's available; I even have one which I made. These are economical approaches to the job. If you have more questions, I would be happy to do what I can to assist.

Jack C.
[email protected]

Hello,
I have a manual, but I can't find the voltage specified anywhere in the schematics or anywhere else, I can tell you the power amplifier is about 2 feet tall with huge cooling fins on it. I have posted the schematic and some other pages from the manual, if you'd like to have a look at: http://www.imageevent.com/hoggravynchtlns (sorry about the large file sizes, I tried smaller and were just illegible) and yes it does have ballscrews. Again thanks for any imput.

Dear Sir:
I have tried to see the schematic from the pics you posted, but cannot make out the details. S-W used to be in our Chicago area but now seem not to be here so getting info may be difficult. One thing you could do if the system works is to measure the + and - DC
voltages in the power supply. My guess is that they will be in the range of +/- 60 volts or so. Assuming that is the case, PWM servo amps would easily be able to handle the motors. You can get PWM servo amps from Gecko or Rutex at a fairly reasonable cost. OR, MAYBE you can use the existing servo amps; they are Linear Amps which means lots of dissipation at low speed, high torque, and that's why they big heat sinks. I think they are rated at something greater than 1 HP and 1200-1400 RPM.
On reading the comments, I'd try to keep the existing motor/tachs as they are probably well built, and they DO fit the system. Also,
one can get brushes if needed. One item of caution, the tachometer may use silver-bearing brushes in order to be more linear.
You might look over the schematic and see if the inputs to the servo amps is +/- 10V. That is/was standard.
Let me know if I can help.
Jack C.
[email protected]

Greetings,
I looked over the schematic, and it's showing 28 volts leaving the "power amplifier" then it goes to the "servo amplifier" then to the servos, no other voltage is specified. You mentioned: "One item of caution, the tachometer may use silver-bearing brushes in order to be more linear" what would the implications of that be? I also wonder if this tach feedback will be compatible with a newer setup? there is only a 5pin connector for the motor and tach, I looked at the wiring of a newer servo motor and it had a ground and 2 leads for the motor and a ground and 6 leads from the encoder. As you can tell I'm no electrical engineer, so I really appreciate the assistance. Thanks

Dear Sir:
If you are serious about continuing on your project, you may contact me off list.
Regards,
Jack C.
[email protected]