The case is a submerged pumping station, with two redundant Flygt pumps for wastewater transport.

The four plots show four different EWA sensor parameters, plotted for the two redundant pumps over a period of 26 days:
Plot 1: Pump unbalance.
Plot 2: Slip speed.
Plot 3: Magnetic Field strength.
Plot 4: Pump operation time for the last 24 hours.

When the unbalance it is observed that the pump 1 has the highest unbalance level. And a quick conclusion could easily and wrongly be that this pump has an unbalance problem.

The unbalance parameter for pump 2 shows a totally straight curve, without any fluctuations – which will never be the case in a normal operation situation. Instead, pump 1 is having clogging problems – also verified by the increased operation time for the pumping cycle and by the increased magnetic strength level.

The conclusion is a clogging issue for pump 1, either in the pump or in the inlet piping to the pump.