It is only appropriate that a person who designs the circuits, knows
what can go wrong with the power units. In the pages to follow we are giving charts describing common problems and remedies that can solve these problems.
These charts also will be very useful for maintenance engineers using
hydraulic power units in their shops. Most of the problems in hydraulic machinery are related to oil contamination. The suction strainer can clog due to contamination. This
can result in cavitation of pump. Contamination can also make the valve
sticky. The DC valve coils can burn due to sticky valves. Another point is that we should ensure oil and air do not mix. They are not made for each other. A loose suction joint can allow system to aerate causing severe pump noise and jerky movement of actuator.
A word of Caution
We have come across problems that are not associated with power unit
but are machine problems or relating to electrical circuits. Therefore
it is essential that before trouble shooting, the problem is identified
to be relating the hydraulics side of the machine.
CHART I-REMEDIES
- Any or all of the following: Replace dirty filters- Wash
strainers in solvent compatible with system fluid-Clean clogged
inlet line- Clean reservoir breather vent- Change system
fluid-Change to proper pump drive motor speed-Overhaul or replace
super change pump-Fluid may be too cold.
- Any or all of the following: Tighten leaky inlet connections-Fill
reservoir to proper level (with rare exception all return lines
should be below fluid level in reservoir)-Bleed air from
system-Replace pump shaft seal (and shaft is worn at seal journal)
- Align unit and check condition of seals, bearing and coupling.
- Install pressure guage and adjust to correct pressure
- Overhaul or replace.
CHART II-REMEDIES
- Any or all of the following: Replace dirty filers-Clean clogged
inlet line-Clean reservoir breather vent-Change system fluid-Change
to proper pump drive motor speed-Overhaul or replace supercharge
pump.
- Any or all of the following: Tighten leaky inlet connections
-Fill reservoir to proper level (with rare exception all return
lines should be below fluid level in reservoir)-Bleed air from
system-Replace pump shaft seal (and shaft if worn at seal journal)
- Align unit and check condition of seals and bearings Locate and
correct mechanical binding-Check for work load in excess of circuit
design.
- Install pressure guage and adjust to correct pressure (Keep at
least 125 PSI difference between valve settings)
- Overhaul replace
- Change filters also system fluid if of improper viscosity-Fill
reservoir to proper level.
- Clean cooler and /or cooler strainer-Replace cooler control
valve-Repair or replace cooler.
CHART III-REMEDIES
- Any or all of the following: Replace dirty filters-Clean clogged
inlet line-Clean reservoir breather vent- Fill reservoir-proper
level-Overhaul or replace supercharge pump.
- Tighten leaky connections-Bleed air from system.
- Check for damaged pump or pump drive-replace and align coupling.
- Check for damaged oum or pump drive-replace and align coupling.
- Adjust
- Overhaul or replace
- Check position of manually operated controls-check electrical
circuit on solenoid operated controls-Repair or replace pilot
pressure pump
- Reverse rotation
- Replace with correct unit.
CHART IV-REMEDIES
- Replace dirty filters and system fluid
- Tighten leaky connections(fill reservoir proper level and bleed
air from system)
- Check gas valve for leakage-Charge to correct pressure-Overhaul
if defective.
- Adjust
- Overhaul or replace
CHART V- REMEDIES
- Fluid may be too cold or should be changed to clean fluid of
correct viscosity
- Locate bind and repair
- Adjust,repair, or replace
- Clean and adjust or replace-Check condition of system fluid and
filters.
- Overhaul or replace
- Repair command console or interconnecting wires
- Lubricate
- Adjust, repair, or replace counter balance valve.
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