FANUC OT B Spindle rpm fluctuating and causing 1008 Spindle Drive Fault

Hi,

I checked all the fuses, and they are ok. After analyzing the AC spindle drive faults, I have one bulb lit in the number two spot. The text for this says "Speed deviates from commanded speed". I read the list of alarms page, and the causes include Overload, transistor module is damaged, loose connections, error with speed feedback signal and blown fuse.

A friend of mine who used to work with GE controllers thinks the frequency and voltage from the drive needs to be adjusted, using the pots on the board. I don't have that manual, so I wanted to ask what the hertz and frequency need to be, so I can adjust that using the pots on the board.
My input voltage checks at 430V 3-phase, and the out voltage from the transformer is 215V 3-phase, which I didn't worry about because it is within 10 percent.
Also, is there a good way to check the transistor module? Any suggestions are appreciated.

Thanks,
Bill Gillen

first , give us the type of spindle drive (A06B-6***-H*** ) or the pcb type (A20B-****-****) or (A16B-****-****)

Hi,

I checked the board, and here is what I saw.

AC SPINDLE SERVO UNIT
Type No. A06B-6052-H001
Mfg. No. P7Y000595


On the boards,
(the one in back) A16B-1100-009?/09D
(the one in front) A16B-1100-0080, Edition 08D

Any information on the spindle drive unit is appreciated.

Thanks again,
Bill Gillen

ok, first thing, you have to check sensor signal by an oscilloscope turning spindle by hand . you have check points at the bottom of the pcb, just near CN2 connector .they are called Pa,Pb, Ra, Rb. You must found a sinusoid of about 3.5 volts on the a, and continuous 3 volts on the two others.

Hi,

My alarms sheet, item 2 under "Speed is deviated from the command value" suggests the Transistor module is defective. The Check Procedure says Transistor collector-emitter is open, and the Remedy is Replace Transistor module.

Is there a simple way to test this transistor module? Or is it one of those situations where you "guess, spend the money and go to the next problem"?

I found this transistor module, and wanted to ask; Is this the module they are talking about?

A50L-0001-0209 Fanuc Transistor Module: Darlington.


Also, if it is, I think I know where it goes, but wanted to ask. I think it goes behind the double stacked circuit board near the center of the cabinet. Is that correct?

Thank you again,
Bill Gillen