[hotrob1]

Mitsubishi Fr-sf-2-26K. Top board SF-CA. Option card SF-BS. The original problem was a dead power supply after running the night before. Replaced PS, then found shorted IGBT in base. Replaced IGBT. Started getting Alarm 23. We tried the top board (SF-CA) on another base; it worked. We had motor checked by motor shop and also megged it out. We put drive in open-loop; it still won't run. We tried another sensor/PLG card; no good. The only thing I know thing know that is left is the SF-BS card. I'm not sure what all this card does. We do not do orientation. I have not ohmed out cabling, but do not think this is the culprit. I may try the other top board out of the good unit but did not want to chance messing it up.

Any thoughts? I hate to send this thing to Mits, but that may be next.....

[botha.y]

Next would be to test the encoder and the encoder cable to see if they're alright.

[Night Shift Wiz]

Next would be to test the encoder and the encoder cable to see if they're alright.

It's an older spindle motor and probably doesn't have an encoder, just a PLG. PLGs cause a lot of weird problems, including blowing transistors. That's what I suspected at first. You need a scope to adjust them.

But he said it won't run in open loop, which bypasses the PLG. That being the case, I'd look hard at the drive. Or perhaps disconnect the PLG and try open loop again. Maybe you didn't follow the right procedure. Also, look at the feedback parameters as a long shot.

[Rokkin]

Does the spindle attempt to rotate in open loop or doesn't rotate at all?? How about closed loop, does it attempt to rotate?? Since you're blowing IGBT's it may be possible you have an open phase between the motor and drive. Check for continuity in the motor cable.

[hotrob1]

Thanks for the repsonses. The spindle will not run in open/closed loop. I also tried a new PLG card/sensor; also adjusted original several times. No help. I tried a new SF-BS card. No help. Since the SF-CA card ran another spindle, I bit the bullit and pulled the entire drive. It's on it's way to Mits. I will keep you posted.