AB Ultra200 Servo Drive

The Ultra 200 suffered from "close tolerance" heat sinking on the electronics. We had a similar problem. System works well when ramped to a stop but shows thermal fault when brought to an immediate standstill by emergency stop. There are terminals incorporated into the unit to fit an external breaking resistor. We fitted this and had no further problems.

If the fault has only recently appeared on old equipment, it may be a sign that the drive electronics are about to fail. You might want to research where you can get a replacement before it fails altogether.

James

I don't have an external shunt on this unit but I'm familiar with it. I had to put one on another indexing line I have that does 145 moves per minute and I was getting the fault on stopping whether normally or e-stop.

What gets me on this situation is that I see no indication of fault when the stop occurs. I am pulling outputs, including fault, from the drive to my PLC as well as looking directly at the drive with the laptop using UltraMaster. The drive appears to be ready to go and the fault does not appear until it it told to go. I can give it a start 100 times and it will fault on start every time until I physically move the motor slightly.

Mark the motor shaft and check if it always stops in the same orientation. That would indicate the fault lies within the motor. It would also explain why your "reset procedure" works. Putting a scope on the motor current might pick up spikes to signal a motor fault, but you need a servo expert to interpret the results.

James

Check if your braking resistors are gone. Looks to me your fault is actually an overvoltage issue from excecssive deceleration+machine inertia to failing brake resistors and deteriorated PS shunt capactitors ratio

S.M