GE QS2800V, QS1800V manual 3.3Operation Safeguards

3.3Operation Safeguards

Quiet Submersible Vertical (QVS) Series pumps are equipped with NEMA standard flow-cooled motors, which are cooled by the process fluid. In general, flow-cooled motors have three requirements for long operational life. They are:

1.A suitable operating environment.

2.An adequate electrical supply.

3.An adequate flow of cooling water over the motor.

Quiet Submersible Vertical (QSV) Series pumps have been engineered to provide a suitable mechanical operating environment and to provide an adequate flow of cool- ing water over the motor, provided the pump is operated between the maximum and minimum flow rates specified for each pump series.

WARNING: CERTAIN SAFEGUARDS MUST BE IN PLACE TO PREVENT THE FOLLOWING OPERATING CONDITIONS:

•Flow rate below minimum specified flow rate

•Close discharge valve (deadheaded condition)

•Dry running

•Fluid temperature greater than 90°F (32°C)

•Low voltage

•Imbalanced three-phase power

Safeguards include low-pressure switches, low-flow shutdown, switches, tempera- ture limit switches, quick-trip circuit breakers and properly-sized motor starter heaters. The three-phase electrical power must exhibit amperage readings in each leg within ±5% of the average for all three legs (Section 3.6.3, Three-Phase Power Imbalance). Consult the motor operation manual for additional information.

3.4Inlet and Discharge - IMPORTANT!

3.4.1Inlet Piping

•Positive feed pressure is required at all flow points.

•Avoid “high points” and other areas where air may accumulate ahead of the pump.

•The inlet piping should be at least as large as the inlet port; pipe size changes should be tapered.

•Sizing pipe to induce 3 psi (0.21 bar) pressure drop or less per 100 feet (30.5 m) is recommended.

•NEVER throttle the pump on the inlet side.

•The pump inlet line should be filled and tested with 20 - 100 psi (1.4 - 1.6 bar) pressure to detect any leaks prior to start-up.

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