Pump motor controlled by Abb frequency drive

[liviu2004]

Hi, I am involved with cooling industry and I saw something that I cannot understand:
- one water pump motor, 480V,60Hz, 265kW, 383A, cos 0,87, T=50 degrees.
- one frequency drive ABB ACS550-02-486A-4
What I do not understand is that: at 81,6%load current is 393A, at around 50Hz. That means more than nominal current of the motor. Also voltage is lower than nominal at 50Hz, of course. The current should not be less than nominal at this 50Hz? Who makes increasing current possible?

 

[Skogsgurra]

It is motor current you are talking about? Not mains current?

If that is so, it looks like you have a slight overload.

It is also possible that the drive is in scalar mode and has been set incorrectly. The "Pump Curves" are not always correct - or using the right "corner point".

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[liviu2004]

Yes, it is the motor current what I read on ABB display. So,it is possible that load on the motor could be bigger and that leads to overcurrent, as the PLC Quantum tries to keep the flow constant as more and more valves are opening. Correct? Maybe is like I power a normal motor to 60Hz power network and I increase load until current reaches nominal current. If I increase more load the current will increase also? Is this a good example?

 

[Skogsgurra]

Yes, that seems to be what is happening.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...