I have a 40hp DC motor in a machine set up for spinning. The motor control (probably built by one of the Apostles) has done something bad and I need to fix it. The system is Reliance and I'm guessing the control is the original in this OLD Given lathe. I haven't used programmable RPM control in the thing for years, I adjust the pot on the spindle control box itself, so I need to figure out some way to make it work.
I don't have anything here on that model number, just some MaxPak and very old (M-G set) V*S drives. Does the motor run at all? If not, check the brush length and fuses, possibly a bad field power supply module.
I'm not familiar with what a motor control on a lathe is expected to do, but I do know motors and controls. I also know you haven't told us much. So:
What is it doing/not doing? What is it supposed to do? What have you done so far? What did you find out? What makes you think it's the controller and not the motor?
What is programmable RPM control supposed to do? Is that what's broken? The pot on the spindle control box? Is that what's broken?
If the motor pulls loads of current but doesn't turn then you may not be getting enough (or any) field current (per the other poster's response). If there's voltage at the field terminals and no field current then the field windings are broken. If there's no voltage at the field terminals then the controller or connecting wires are broken.
If the motor doesn't pull current and doesn't turn then either it isn't getting any voltage or something internally is broken - brushes, armature wires, commutator, etc.
John, I don't know if you are willing to send it out but if you are there is an outfit called "Electrical South" that may be able to fix it. 4 years ago I had a 10 HP "Randtronics" brand DC motor drive fail. They were the only folks I could find who were able to fix it for less than a new DC drive. They charged a $500.00 flat fee. I think these folks are the ones you want: