ABB ACS 141 Inverter drive

Sparkattack · Feb 5, 2013

Was asked to look at a fault with a pump that had been reported to have tripped a couple of times over the last few weeks. The setup is a ABB ACS 141 inverter drive(230Va.c) wired to a 2.2KW 1phase/3 phase motor, wired in delta at the motor 220v/240v supply. The pump ran up ok if not sounding a little rough! I firstly tested the motor and windings are balanced 2.25ohms, i then proceeded to check voltages. Drive input 230Va.c, but tested output at motor terminals between 180V to 200V? At this point the drive was only running at about 23Hz, clamp meter showed 3.4amps. This drop in voltage at the output suggests to me an issue with the drive. I then checked pump 2 which is identical setup to try and confirm this but that pump also tested out the same? Is there something I am missing? I'm convinced its a drive issue but its strange that both drives are the same!

Knobhead · Feb 5, 2013

If the pump sounds rough I’d be inclined to have a look at that first. What sort is it? Inverters are great at protecting the motor, but at times they are a bit over enthusiastic doing it. One way of checking the loading is to measure the input current to the inverter and work from there, it takes away any problems with frequency. But don’t forget the internal losses.

SheffSimon · Feb 5, 2013

Sparkattack said:
Was asked to look at a fault with a pump that had been reported to have tripped a couple of times over the last few weeks. The setup is a ABB ACS 141 inverter drive(230Va.c) wired to a 2.2KW 1phase/3 phase motor, wired in delta at the motor 220v/240v supply. The pump ran up ok if not sounding a little rough! I firstly tested the motor and windings are balanced 2.25ohms, i then proceeded to check voltages. Drive input 230Va.c, but tested output at motor terminals between 180V to 200V? At this point the drive was only running at about 23Hz, clamp meter showed 3.4amps. This drop in voltage at the output suggests to me an issue with the drive. I then checked pump 2 which is identical setup to try and confirm this but that pump also tested out the same? Is there something I am missing? I'm convinced its a drive issue but its strange that both drives are the same!

Depending on the inverter setup, quite normal to have inverter in V/f control where the the voltage output varies with frequency. I would also be more inclined to look at the inverter output current rather than clamping it.

Can you look back at the alarm history in the inverter to get the alarm codes?

stef · Feb 5, 2013

Sparkattack said:
Was asked to look at a fault with a pump that had been reported to have tripped a couple of times over the last few weeks. The setup is a ABB ACS 141 inverter drive(230Va.c) wired to a 2.2KW 1phase/3 phase motor, wired in delta at the motor 220v/240v supply. The pump ran up ok if not sounding a little rough! I firstly tested the motor and windings are balanced 2.25ohms, i then proceeded to check voltages. Drive input 230Va.c, but tested output at motor terminals between 180V to 200V? At this point the drive was only running at about 23Hz, clamp meter showed 3.4amps. This drop in voltage at the output suggests to me an issue with the drive. I then checked pump 2 which is identical setup to try and confirm this but that pump also tested out the same? Is there something I am missing? I'm convinced its a drive issue but its strange that both drives are the same!

Of course they will be the same. Try to run a three phase motor at a low frequency,
it will burn out, the lower the frequency the lower the impedance the higher the current. Modern inverters do lower the voltage with decreasing output frequency. Did you check the insulation resistance of the motor? But as suggested above, more than likely a mechanical failure of either the pump or the motor. Look at this first.
the inverters are likely to be OK.

Sparkattack · Feb 6, 2013

Thanks for all your replies.
The pump is a multistage inline type, the pumps maintain a pressure of 6.5bar through a PID loop, pumps water so depending on demand the inverters ramp up and down.
The motor checked out fine balanced windings and insulation resistance. I think the drop in voltage at the motor stumped me so as has been suggested I think a mechanical issue might be to blame. Although these little pumps are pretty reliable usually! I will check parameters and alarm history as I now have access to a manual