Fanuc OT - Spindle problem

[Juanma]

Hi everyone, I'm trying to repair a CNC Lathe, with a Fanuc OT controller, when you try to move the spindle, it doesn't move, the spindle load meter grows up to 50% of load, and the spindle continues without moving, after a few seconds the screen shows not ready and stops the action, but doesn't display any alarm. The Spindle controller is a Mitsubishi Freqrol FR-SF-2-11K-T, in his little display doesn't show any alarm, but if you open the plastic cover there are some leds on, but without any ID. I have checked the wires and they looks good. The DC BUS is ok.
Does anyone knows something about this problem? Anything you can tell me about this will be very helpful.

Thanks to all.


Hopefully this is the right sub-forum to post this in.

[fizzissist]

Just exactly what do you mean by "trying to move the spindle"???

If the spindle is activated by an M03 or M04 without an RPM specified by an S word, the spindle will sit there and when you try and physically move it the load meter will register. This is potentially DANGEROUS.

If not under power, the spindle should rotate freely.

So, are we talking about a technical electrical problem or a programming/operation issue? What do you mean by "repair"?

[Juanma]

Hi fizzissist, thanks for your Fast answer. When I say “trying to move the spindle”, I try to move the spindle in manual mode, without running any program.
I didn’t move the spindle physically when I try to move it in manual mode, but I have checked that the spindle rotate freely before any test, and it was ok.
The spindle load meter grow up to 50% immediately after I push the button to move it,
Also I have checked the Spindle drive output voltage and it was 0V.
When I opened the Spindle Drive plastic cover, I saw 12 MosFet, they shoot the IGBTs, I checked some of them and they were good.

I think it is a technical electrical problem.

[gridley51]

Do you mean you are programming a spindle speed in mdi?
You can download a manual for the Freqrol from Mitsubishi Electric Automation Inc. - MEAU Home
What machine is it on?