[p1etaster]

Hi,
I'd appreciate some help/advice.
I have a Fanuc 0T (circa 1989) with what I believe are S series ac servos.
It is coming up with alarm 400 (overload).
I have read that the 400 alarm can be caused by the motor overheating. Is there therefore a thermal switch/thermistor in these motors? If so does anyone know where they may connect into the control/servo? (note: the motors are not getting hot and the error is there at power-up, there is some damage to the cable chain running to the x axis therefore a possible broken cable)
I have no electrical drawings for this machine, and only an operator manual for the 0T. There are some connections along the bottom of the servo card (adjacent to the incoming power and motor connections) labeled something like 100B or IO0B - is this the thermistor connection?
Many thanks.

[Al_The_Man]

If you take the red cap off the rear of the motor, you will see the encoder cable and also a pair of individual wires, usually white or black that come out of the motor winding, this is the thermal sensor.
These go to the canon connector and should measure closed circuit.
The termination for these are usually labeled OH1 OH2 etc.
Depending on the drive, these usually end up in the Honda connector on the bottom of the drive.
100A 100B are usually a 100vac input.
What is the model of drive?
Al.

[p1etaster]

Thanks for your reply Al,
Seemed to have got it fixed today...it was a cable problem as suspected.
Cheers,
James