28
Pump takes too much power
CAUSES
CURES
32. Head lower than rating; thereby
pumping too much liquid.
Machine impeller's OD to size advised by factory.
33. Cavitation
See item 14.
34. Mechanical defects
See items 15, 16 and 17.
35. Suction inlet not immersed
enough.
See item 18.
36. Liquid heavier (in either viscosity or
specific gravity) than allowed for.
Use larger driver. Consult factory for recommended size. Test liquid
for viscosity and specific gravity.
37. Wrong direction of rotation.
See item 6
38. Stuffing boxes too tight.
Release gland pressure. Tighten reasonably. If sealing liquid does
not flow while pump operates, replace packing. If packing is wearing
too quickly, replace scored shaft sleeves and keep liquid seeping for
lubrication.
39. Casing distorted by excessive
strains from suction or discharge
piping.
Check alignment. Examine pump for friction between impeller and
casing. Replace damaged parts.
40. Shaft bent due to damage through
shipment, operation or overhaul.
Check deflection of rotor by turning on bearing journals. Total
indicator run-out should not exceed 0.001 on shaft and 0.004 inch on
impeller wearing surface.
41. Mechanical failure of critical
pump parts.
Check bearings and impeller for damage. Any irregularity in these
parts will cause a drag on shaft.
42. Misalignment
Realign pump and driver.
43. Speed may be too high (brake
hp of pump varies as the cube of
the speed; therefore, any increase
in speed means considerable
increase in power demand).
Check voltage on motor.
44. Electrical defects
The voltage and frequency of the electrical current may be lower
than that for which motor was built; or there may be defects in motor.
The motor may not be ventilated properly due to a poor location.
45. Mechanical defects in turbine,
engine or other type of drive
exclusive of motor.
If trouble cannot be located, consult factory.
