The preventive maintenance is carried out on hydraulic systems to keep them in a perfect working condition at all times. However, faults or breakdowns do occur in hydraulic systems, which have to be traced and corrected with minimum delay and expense. Table below gives pump malfunctions and their potential causes and rectification.

Disturbances	Possible causes	Rectification
Loud pump noise	Cavitation	-Clean dirty strainer/filters -Replace defective filters -Use filter of correct size -Change system fluid -Maintain fluid level in reservoir -Warm up fluid, if too cold -Clean reservoir breather vent -Correct drive motor speed
Hot pump	Hot fluid	-Increase reservoir capacity -Change system fluid -Change filters -Clean/replace cooler
Low pump discharge	Low flow	-Replace with correct type -Set valve correctly -Replace or overhaul -Tighten leaking connections -Adjust swash plate angle correctly
Pump slows down or stalls	Low voltage supply	-Provide correct power supply
Pump slows down or stalls	Drive motor in Star connection	-Re-wire in Delta connection
Motor turns backwards	Phase reversal	Interchange any two phases
Motor erratic/ not operating	Wrong motor wiring,	-Re-configure wiring
Motor erratic/ not operating	Wrong power supply	-Provide correct power supply

References:

Categories of malfunctions in hydraulic systems in terms of its general disturbances, and their possible causes and rectification are presented in the above books. Further, the component-wise malfunctions and their potential causes and rectification are also presented.

Joji Parambath

Director

Fluidsys Training Centre