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

[Bill Gillen]

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

[tmbruno28]

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

[Bill Gillen]

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

[tmbruno28]

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.

[Bill Gillen]

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