Monitoring Submersible motor pump  health for water application

Check points (monitoring points) by pump operator ( Look Listen Feel and Record Approach)

by pump operator:

1. Observe and Record the discharge pressure gauge reading (must have been installed in discharge

piping system).

If the reading is significantly oscillating (hunting to and fro) more than 15-20% of normal

operating point, it gives following signals which can be addressed through skilled service

technicians:

1.1. Strainer might have been choked due to mud /debris/scales accumulation around the

strainer. Needs cleaning of strainer.

2. Abnormal noise coming out from the piping system which is a signal of Cavitation phenomenon

in the system. This may be due to starvation in the pump. Remedy suggested is same as in point

no 1.1 above. OR level of water in underground water tank is lower than strainer location.

Pumps need not to be started unless level in water tank is adequately maintained.

3 Pump is running but with no flow or significantly reduced flow and with shut off pressure ( which

is more than operating pressure):

This indicates that NRV installed in discharge piping system is jammed ( not opening ) .Needs

inspection of NRV.

4.Pump is getting tripped after start of few seconds . This gives signal that

4.1 Either NRV is heavily passing ( WORN OUT FLAPPER ) and discharge valve is in full open

condition. Leading to over load of pump motor . OR

4.2 Pump motor bearing is damaged .

Measurement of motor current will confirm the over loading . This Needs inspection of NRV.

5. Pump is not getting started at all. Following needs to be checked:

5.1 IR value ( Insulation resistance) of wiring of motor. If IR value is less than 0.5 MegaOhm

needs inspection of wire /winding to fix the issue by skilled SERVICE electrician.

5.2 If IR value is within normal limit, still pump is not getting started then it needs inspection of

pump internals for bearing seizure with motor shaft either due to increased clearances or due to

lack of cooling by water as lubricant/coolant. Submersible pump sleeve bearing is water lubricated.