PowerFlex 400 - Output frequency issue

[PaulKim1003 3]

Hi,

I have a few PowerFlex 400 drives and One of them is acting really weird.

I set the speed setpoint to 13Hz but it can't go over 1 hz. It is beeping and it says it is accelerating in CCW but it is not going over 1 hz. 

It is like a sine wave. Going up and going down and continue doing this.

I compared the parameters with the other powerflex 400's but it is identical..

I think it is an electrical problem but I just want to post it here to know if anyone had same issue before.

Thanks 

Have a great weekend,

[VFD Guy 13]

The basics of VFD troubleshooting is to identify if the VFD is doing what it’s told. Compare commanded speed with output. Based on what you’ve stated it sounds like it’s not. This tells me the drive is hitting a limit and folding back. There should be alarms and limit statuses you can monitor. Another quick trick if you are in an open loop mode is to run without motor connected. If the it still cycles, you know to focus on the drive. If not, it’s a load or failure of the drive. At that point, I’d be looking at the logged alarms to understand more. There are regulators in the drive to overwrite the command to protect itself