What happens when charge pump pressure is too low?
What happens when charge pump pressure is too low?
With this condition the charge pump pressure may fall very low, too low to stroke the pump to more than a small cam angle. The result is that the hydraulic motor cannot develop full speed under high torque conditions. The remedy for this condition is a major pump overhaul. 3. Measure High Pressure.
What to do if your hydrostatic system has no charge?
If there is no charge pressure at any position of the control lever, the charge pump is probably at fault. Suspect a broken drive shaft or coupling to the charge pump. To confirm the diagnosis, remove the charge pump cover and inspect for broken parts.
How does the charge pump in a hydrostatic system work?
The charge pump will supply makeup oil through the check valve, preventing pump cavitation. The charge pump is also used to supply oil to the spring-loaded cylinders for stroking the main pump. The charge pump relief valve provides a flow path for the excess pump volume to return to the tank in idle mode.
What should I do if my pump inlet strainer is not working?
If cleaning the pump inlet strainer does not correct the trouble, isolate the pump and relief valve from the rest of the system by disconnecting the plumbing at Point B and capping both ends of the disconnected lines. This deadheads the pump into the relief valve.
With this condition the charge pump pressure may fall very low, too low to stroke the pump to more than a small cam angle. The result is that the hydraulic motor cannot develop full speed under high torque conditions. The remedy for this condition is a major pump overhaul. 3. Measure High Pressure.
If there is no charge pressure at any position of the control lever, the charge pump is probably at fault. Suspect a broken drive shaft or coupling to the charge pump. To confirm the diagnosis, remove the charge pump cover and inspect for broken parts.
What to do if your closed loop hydrostatic system is stuck?
If there is little or no rise in loop pressure when the control lever is moved out of neutral, one of the high pressure relief valves (usually located in the motor rear cover) may be stuck or damaged. Since there are two high pressure relief valves, one for each direction of operation, try moving the lever to both forward and reverse.
Where is the charge pump on a hydrostatic system?
The charge pump is separate from the main pump and is located in the rear cover of the main pump. Its purpose is to continually re-circulate cooled and filtered oil into the main loop. It is a fixed displacement pump delivering about 10% of the volume of the main pump.
