Just got back from a call-out to a plant that was having issues with a AB 525 drive. Ethernet control(start/stop/reference), and the speed reference was a static set-point....I guess it was just there so an operator could speed up the conveyor as needed.
It runs a dynamic motion conveyor that swings large weight via a gearbox, to convey product without damaging its structure.
Started last Thursday evening go an "OverVoltage" fault. Checked it out and everything seemed fine. Checked out a few parameters to see if there was an issue, and didn't see any. the drive reset without issue and ran almost exactly 24 hours.
Friday evening, again the drive faulted on "OverVoltage" again. Checked logic to make sure there was no possibility to chatter the start/stop on the drive. Decided to enable "Flying Start" in case that might have been it, checked the regulator compensation and it all seemed fine. Had some trouble resetting the drive, as it would run the conveyor about 5 minutes and fault again. Eventually it reset, and ran almost exactly 24 hours, before faulting again.
Saturday evening I tried to reset it, and again it would run maybe 5 minutes or so, then fault "OverVoltage". Watching the DC bus, and I never see it rise above 706VDC. I think it has to reach over 800VDC to trip on overvoltage. I've noticed that they have been running this conveyor lately at 60Hz continuously, so I set a lower set-point into it to slow it down a bit (55Hz).
This is where it gets weird. I can see that the "Commanded Frequency" is 55Hz, but the drive output hangs around 58-59.5Hz...and the drive status hangs on decelerating, and never changes from that.
We are currently oversold on product, so I've been getting an earful from higher-ups. I couldn't figure it out, and didn't have a spare 525 in that size, so moved it to a across-the-line starter as a temporary fix.
Anyone seen this behavior? I searched the knowledge base, and all the suggestions I saw related to a regenerative action from the motor, but I had "stop" set to coast, not ramp down the motor....and there was no wild fluctuation of reference, but a digitally set set-point.
It runs a dynamic motion conveyor that swings large weight via a gearbox, to convey product without damaging its structure.
Started last Thursday evening go an "OverVoltage" fault. Checked it out and everything seemed fine. Checked out a few parameters to see if there was an issue, and didn't see any. the drive reset without issue and ran almost exactly 24 hours.
Friday evening, again the drive faulted on "OverVoltage" again. Checked logic to make sure there was no possibility to chatter the start/stop on the drive. Decided to enable "Flying Start" in case that might have been it, checked the regulator compensation and it all seemed fine. Had some trouble resetting the drive, as it would run the conveyor about 5 minutes and fault again. Eventually it reset, and ran almost exactly 24 hours, before faulting again.
Saturday evening I tried to reset it, and again it would run maybe 5 minutes or so, then fault "OverVoltage". Watching the DC bus, and I never see it rise above 706VDC. I think it has to reach over 800VDC to trip on overvoltage. I've noticed that they have been running this conveyor lately at 60Hz continuously, so I set a lower set-point into it to slow it down a bit (55Hz).
This is where it gets weird. I can see that the "Commanded Frequency" is 55Hz, but the drive output hangs around 58-59.5Hz...and the drive status hangs on decelerating, and never changes from that.
We are currently oversold on product, so I've been getting an earful from higher-ups. I couldn't figure it out, and didn't have a spare 525 in that size, so moved it to a across-the-line starter as a temporary fix.
Anyone seen this behavior? I searched the knowledge base, and all the suggestions I saw related to a regenerative action from the motor, but I had "stop" set to coast, not ramp down the motor....and there was no wild fluctuation of reference, but a digitally set set-point.