Hi folks, exhaust fan on the cure area, PowerFlex 525, 5.5kW frame, 415V. Runs all shift no problem, but every time the operator hits stop it trips F005 OverVoltage. Reset it, start it, runs fine again until the next stop.
I measured the incoming at the disconnect, gloves on and the 1000V meter, 425V phase to phase, all three within 2V. Bit high, but we've been at 425 on this MCC for years. A lad I used to work with reckoned there was a bad batch of these going round, so we put the spare off the shelf in as well and it faulted on the first stop.
So two drives doing the same thing. Is 425 too high for a 525, or did we get two bad ones? It's only ever on the stop and never while it's running, so I reckon it's the decel and not the 425, but two of them doing it has me second guessing.
425 is well inside the range for a 400 volt drive, ours sit high too. So that's not your problem. Two questions before anything else. What's P042 set to, the decel time? And what's on the shaft, a direct wheel or belts?
P042 says 3.0. When we put this drive in last year we copied the parameters off the conveyor drive next to it, same size frame I think.
Direct wheel on the motor shaft. It's a big one, close to a metre across, steel.
A wheel that size won't stop in 3 seconds.
Same as dan says. During the 3s decel the drive pulls the frequency down faster than that wheel can slow, so the wheel drives the motor, the motor turns into a generator, and the DC bus climbs. Above the trip point the drive faults F005 to save itself. Neither drive is bad.
Conveyor decel numbers never suit a fan. Set P042 to 25 or so and watch the bus voltage on the display while it stops. Still creeping up, go longer. If the stop time actually matters for the process, that's a brake resistor on the DB terminals, not a shorter decel.
There's a writeup on the decel and braking side here: https://plctr.com/utilizing-plc-for-motor-control-and-drive-systems/
Tried 15 first. Still faulted once out of five stops. Went to 25 and it stopped clean all afternoon, bus climbed to just over 700 on the display and came back down.
A conveyor decel time and a metre of steel wheel behind it, that was the lot. P042 from 3 to 25 and neither drive was ever sick.
Only thing bugging me is the old drive we pulled is sitting in the scrap bin with a tag on it. It was fine all along.
Thanks vinnie86 and dan.
Pull the old one out of the bin. Nothing wrong with it.