Docs for old motorized GE Volt Pac


Thread Starter

Steve Myres

I have a GE VoltPac variac that believe is configured for automatic voltage regulation, similar to what would have been used in an Advantx X-Ray or other GE Medical product.

The variac (GE 9T9A3052)is actuated by a motor that looks similar to a shaded pole motor, with one winding in the place where a shaded pole motor would normally have it, and three additional leads on the other side of the core. This second set of leads must control the motor rotation, because one goes straight from the control PCB (46-225696 G1) to the motor and the other two connect to the motor from the board through two end-of-travel limit switches.

I have an application where I would simply like to be able to remotely run the motor forward and reverse to control the variac, and using the limit switches would be fine as well. I have no problem using the controller if it's appropriate to the application and if I can find docs on how to connect to it, but pitching it and driving the motor directly with relays is fine too.

I've been unable to find any documentation on this controller (I could infer from the controller docs how the motor is being controlled and duplicate it myself with relays) on Google or GE Medical's website (haven't called them yet).

I've been able to find docs for the Volt Pac product from Superior Electric, who eventually purchased Volt Pac, but of course that uses a simple three lead synchronous motor that you wouldn't even NEED any documentation for! Isn't that always the way.

Do any of you all have, or know where I could find, any documentation on the board, the entire assembly, or the motor itself?
OK, the additional control leads seem to go to shading coils wound with fine wire, so you connect the common and one of the other two and you've completed one shading coil (through the limit switch) and the motor runs in full speed in the direction determined by which lead you connected to the common.

Additionally, the control board uses triacs as the switches that it interposes in the direction-control coils, presumably to slow down the motor as you approach the desired setting on the variac. So I've disconnected the control leads from the PCB. I'm going to hard wire them in one direction with no speed control and see what the resulting speed is. It may be fine as is, and if not, I'll apply speed control as was originally used.