Inspection Procedure For Centrifugal Pump And Motor

Pump:

1. Impeller, pump shaft and internal volute/casing can now be inspected for erosion, pitting and wear.

2. If required rectify pitting or erosion in the impeller and casing with two-part alloy epoxy putty. (See my article in the Reference section)

3. Check main drive shaft bearings and thrust bearings for wear and replace if required.

4. Check wear ring clearance using feeler gauges; in my day at sea, it was general practice is to replace with new rings at major overhaul.

5. Check impeller/shaft key and keyways for damage and undue wear, Unscrew impeller shaft securing nut and check threads are in satisfactory condition; retighten to manufacturers torque settings.

6. Give all parts a good clean removing any dirt/ medium residue before reassembly using new parts as required.

7. Enter the date of overhaul and parts renewed in the pump maintenance record card.

Drive Motor:

1. Grip motor drive shaft /coupling firmly and check for excess axial and longitudinal movement. Rotate shaft at speed by hand, allowing it to run to a stop whilst listening for excess noise from bearings. Any doubt on either count, the bearings should be replaced.

2. Megger checks motor windings to ensure no dampness is present and windings are in good condition. Any suspect readings indicate a full motor strip to check the condition of the rotor and stator.

3. If these checks are satisfactory, grease bearings as required. Some bearings are now sealed for life and will not require greasing.

Procedure to Start the Pump:

1. Unlock and remove chains from inlet/outlet valve wheels and open both valves full.

2. Open-air cock and expel air from line and pump while checking for any leaks

3. Turn the shaft coupling and ensure the shaft is free to rotate.

4. Reconnect motor.

5. Remove danger notices from pump power supplies and reinstate breakers.

6. Start and record current drawn by the motor under starting and running conditions. Check and record the discharge pressure.