ACS1000 Drive Unbalance NP fault 2

[Sanjay Patel]

Dear friends

What could be the reason for Unbalance NP fault in ABB ACS1000 Vfd drive.?

While charging the VFD drive, after 10 to 15 seconds trip command is generated for CB by VFD as Unbalance NP.

Following are the sequence of events for trip

Unbalance NP
Int MCB trip Req
Trip Loop
AMC fault class 1

 

[Gr8blu]

Check the following thread:

https://www.eng-tips.com/viewthread.cfm?qid=496873

Converting energy to motion for more than half a century

 

[waross]

Have you checked the phase voltages to ground?
If the supply is from an ungrounded source, the source neutral may be displaced from ground.
That could lead to the internal neutral point being offset from a ground reference.

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