Yaskawa J7 Vfd Giving Oc Fault Without Motor Connnected

If it was used on single phase, it may be that the capacitors went from the increased ripple. If you have a capacitor tester you could remove them and test each capacitor, more than likely more than one things fail in a cascade and probably toasted.
 
Gonna sound dumb maybe, but you realize this is a 3 phase input VFD right? Did you connect it to 3 phase power or single phase?



Never mind, I didn't see where you said you were going to try connecting it to 3 phase next.
 
Thanks for replying. It is a 3p unit but when I contacted Yaskawa, they say that it can definitely be connected to 1p but the drive has to be derated by about 60-70%. I did try it on 3p though and it didn't work either.
 
What kind of motor are you connecting it to? Voltage, number of phases, hp rating, etc? Also, recommend you take a multimeter between each phase of the motor and between each phase and the motor ground and report the resistance reading.

I am inclined to think that this could be a bad motor vs a bad VFD.

Techie1961 said:
It powers up the display okay and I can do programming on it but when I try to put it in RUN mode, I get an OC message right away. Even without a motor attached.
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Notice the "magnetic contactor open on the inverter output side" in the excerpt of the manual you posted. What that is telling you is if you push RUN without a motor attached (which you shouldn't do), you will get the OC warning to tell you no motor is attached.
 
tmarks11 said:
What kind of motor are you connecting it to? Voltage, number of phases, hp rating, etc?



Notice the "magnetic contactor open on the inverter output side" in the excerpt of the manual you posted. What that is telling you is if you push RUN without a motor attached (which you shouldn't do), you will get the OC warning to tell you no motor is attached.
Click to expand...
Interesting! I'll have to check it out again. When I talked with Yaskawa, they seemed to think that if the output was empty and there was an OC, it was definitely no good. Will let you know though. Thanks!
 
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