Dear all,
we have a 75kW pump submersible pump with Star-Delta control. It came to my notice recently that the starting current of one of the pumps is 21A (others that we have typically have a starting current of 160A) while the running current is 55A (as against 70A for the others). The speed of the pump is also lower than that of the other pumps.

Does anyone have any ideas as to what the problem may be? Previous experience and how the problem was solved?Your support will be most appreciated.

Truly, I have not experienced this kind of situation before.

Regards,
VMAC100

I don't have much specific: just very general comments in order from most likely to least likely:
1 - most likely the motor is miswired. For a dual voltage motor there can be 4 winding configurations shown on the nameplate. series/star for 460v start. series delta for 460v run. parallel star for 230v start. parallel delta for 230v run.
2 - check for current balance.
3 - make sure you're monitoring current at a location that captures the phase current.
How low was the speed of this machine and what is the speed of the others? Do they drive pumps in parallel?

I am curious how motor/pump speed was measured. A reduction in speed implies an increase in load and therefore an increase in current. If both speed and current are low, then there must be insufficient current/voltage to get to normal speed. Does this make any sense?

Walt

VMAC100
I have to assume the pump output is reduced, true?
What's changed? Has the pump/motor/starter been worked on recently or is his a completely new development?