Machine:
1990 Cincinnati Sabre 750 with Fanuc motors and drives
A06B-6059-H212#H570 Spindle Drive
A06B-0728-B104#3800 Spindle Motor
Back Story:
A few weeks back while dry running a program, spindle was at 8k (which is wide open on this machine), when suddenly I hear the RPM start to ramp down. I hit feed stop and spindle stop... spindle doesn't stop so I hit the E-stop.. still doesn't stop. The spindle ended up just free spinning until it finally slowed to a stop about what seemed like 5 minutes later. Get everything booted back up, and everything is as normal, until I try to call a tool. When the spindle goes to spin up and orient for the tool change the spindle turned VERY slowly, then the spindle drive errors out with an AL-12 code.
Tested the motor with a megohmmeter and got 200 megs on two legs, and 300 on the third, testing with the motor disconnected from the cables, leg to ground. Tests the same through the cables to the motor, and cables show no continuity when disconnected on both ends. Spindle turns free and smooth.
Next I tested the transistors. One transistor block tested out of spec, so I decided to replace both of them while I was in there. Go to fire back up, now spindle doesn't spin at all, same AL-12 fault. At that point I decided to just replace the drive, and got a used drive off eBay. Replace drive, no change, spindle doesn't move, still AL-12 fault.
I'm stumped at this point. I don't want to continue throwing parts at this thing. What am I missing? Are there tests I can do that I've overlooked?
1990 Cincinnati Sabre 750 with Fanuc motors and drives
A06B-6059-H212#H570 Spindle Drive
A06B-0728-B104#3800 Spindle Motor
Back Story:
A few weeks back while dry running a program, spindle was at 8k (which is wide open on this machine), when suddenly I hear the RPM start to ramp down. I hit feed stop and spindle stop... spindle doesn't stop so I hit the E-stop.. still doesn't stop. The spindle ended up just free spinning until it finally slowed to a stop about what seemed like 5 minutes later. Get everything booted back up, and everything is as normal, until I try to call a tool. When the spindle goes to spin up and orient for the tool change the spindle turned VERY slowly, then the spindle drive errors out with an AL-12 code.
Tested the motor with a megohmmeter and got 200 megs on two legs, and 300 on the third, testing with the motor disconnected from the cables, leg to ground. Tests the same through the cables to the motor, and cables show no continuity when disconnected on both ends. Spindle turns free and smooth.
Next I tested the transistors. One transistor block tested out of spec, so I decided to replace both of them while I was in there. Go to fire back up, now spindle doesn't spin at all, same AL-12 fault. At that point I decided to just replace the drive, and got a used drive off eBay. Replace drive, no change, spindle doesn't move, still AL-12 fault.
I'm stumped at this point. I don't want to continue throwing parts at this thing. What am I missing? Are there tests I can do that I've overlooked?