PowerFlex 4

Hey guys I have a PowerFlex 4 22A-D6P0N104 3 phase in/out 415v.

I have a fault that comes up only between 40-50 Hz after around 10 minutes of F3 Power Loss?? It runs OK under 40Hz. I am at a Loss as to why this is happening, I have tested incoming voltage and appears stable at 415v.

Any comments?

thanks
hazey

My guess would be you have lost one of your incoming phases. Possibly by a loose wire or blown fuse, etc. A single phase is probably enough to maintain the buss voltage up to 40Hz, but then your power demand probably surpasses what the single phase can supply.

Have you checked phase to phase between all phases right at the drive terminals?

Yes all good on voltages, 415v across all phases.

Generally speaking, the power loss fault is an indication the drive can't maintain buss voltage. Since your certain all three phases are fine this narrows the options pretty quick. You should monitor the bus voltage over the that 10 minute span from power up to failure and see if it is just gradually dropping (just monitor d005). You should also check the setting for the trip thresholds.

It may simply be a bad drive. One of the caps may be bad and no longer taking a charge or a bad buss to cap connection. Is this a new installation or something that has been running for some time?

Yes new installation, I did check Buss voltage but only briefly, not the whole time. Buss Voltage was 610-620v. I will check from startup to failure in the morning. The 2.2kw motor is on a seed grader and is fully loaded.

thanks

hazey

Yes, the big point of interest is where the buss voltage is at around the time it goes south. Looking at my prior post, I also forgot to include possibly an open bridge on your rectifier. We can rule out that by putting an amp probe on all three feeds and verifying you are drawing ballanced current on all of them.

Just to close this out I had to install 4kw drive on 2.2kw motor to fix problem, must have been load related?

thanks

hazey