 |
Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility. |
 |
This test is designed to determine whether a pump is operating within design parameters.
For any pump test, the pump flow at 690 kPa (100 psi) will be larger than the pump flow at 6900 kPa (1000 psi) if the pump is operating at the same rpm. The pump flow is measured in L/min (US gpm).
The difference between the pump flow of two operating pressures is the flow loss.
 | |
| Illustration 1 | g00985370 |
 | |
| Illustration 2 | g00985371 |
Flow loss that is expressed as a percentage of pump flow is used as a measure of pump performance.
 | |
| Illustration 3 | g00985372 |
 | |
| Illustration 4 | g00985374 |
If the percent of flow loss is greater than 10%, the pump performance is inadequate.
Note: The values in the examples are not set values for any specific pump or for any specific pump condition. See the Specification for your machine for the pump flow of a new pump at 690 kPa (100 psi) and at 6900 kPa (1000 psi).
Machine Test
Install a flow meter. Run the engine at high idle. Measure the pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi). Use these values in the following formula.
 | |
| Illustration 5 | g00985375 |
Bench Test
If the bench test can be performed at 6900 kPa (1000 psi) and at full pump rpm, determine the percent of flow loss by using the above formula.
If the bench test cannot be performed at 6900 kPa (1000 psi) or at full pump rpm, run the pump shaft at 1000 rpm. Measure the pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi). Use these values in the top portion of the following formula. For the bottom part of the formula, run the pump shaft at 2000 rpm. Measure the pump flow at 690 kPa (100 psi).
 | |
| Illustration 6 | g00985376 |