Over current tripping on ABB ACS850 frequency drives

[fiaz1404]

Three ABB ACS850 drives installed in our facility for different applications started to trip with over current(different occasions). After ruling out the possibilities of over current due to load issues, defective motor and cables, we found that value of measuring parameter 01.07(DC-voltage) is < 350V which is far less than expected value 680 volts. Please note that drives are connected with 3 phase 480 v A/C Supply. Actual DC-Voltages, we measured on DC bus with our Fluke device were 680 Volts. Drives were replaced with new units and problem was resolved.

I request you to give expert opinion regarding the problem.

 

[Skogsgurra]

I've had similar issues with the "Cousin" ACS 880. Invariably, it turned out to be the DC-link fed DC/DC supply for the control electronics. That unit also delivers DC link actual voltage for supervision and control.

Not sure if it also handles the I[sub]act[/sub]. But if it does and is defect, you will surely have problems.



Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[jraef]

Not sure if this is related, but years ago i was working on some soft starters that kept tripping on what appeared to be short circuit level current, but we could never see it with independent meters or scopes. Turned out the main board used a DC/DC power supply board for powering an aux board for metering. The chopper kept artificially limiting the voltage sensing circuit voltage, which then skewed everything else to where the board was telling the system that the current went instantly to 65,536A. The problem was eventually traced to a defective A/D chip in the chopper that was overheating well under spec, taking all of the bits in the register high at once. We had to recall all of those boards.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[iop95]

DC bus voltage sensing circuit problems and/or software error in converting/scaling real value.