TM 5-3895-383-24
Flow loss that is expressed as a percentage of pump flow is
used as a measure of pump performance.
Table 3
Method of determining percent of flow loss:
Flow loss (L/min or US gpm)
Pump flow at
690 kPa (100 psi)
X
100
Percent
=
of flow
loss
Table 4
Example of determining percent of flow loss:
20.8 L (5.5 US gal)
217.6 L/min (57.5 US gpm)
X
100
=
9.5%
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.
Table 5
Pump flow at 690 kPa
(100 psi)
Pump flow at 6900 kPa
-
(1000 psi)
Pump flow at 690 kPa
=
Percent
of
flow loss
(100 psi)
X
100
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).
Table 6
Pump flow at 690 kPa
(100 psi)
Pump flow at 6900 kPa
-
(1000 psi)
Pump flow at 690 kPa
=
Percent
of
flow loss
(100 psi) and 2000 rpm
X
100
Travel Speed - Test
SMCS Code: 7000-081-V6
NOTE:
The machine must be in high speed range for this
test.
The oil in the system must be SAE 1OW hydraulic oil. The oil
temperature must be at 38C (100F) in order to get correct
results. All speed tests are made with the engine rpm at
maximum rpm.
Time the machine in forward and reverse through a
30.5 m (100 ft) timing trap. The vibration system must be off.
NOTE:
The machine must be at top speed through the
entire timing trap.
The circuit operation is normal if the travel speeds match the
speeds on the following chart. The relief valves for both the
charge circuit and the propel circuit must be tested in order to
be sure that the opening pressures are correct.
Table 7
Travel Time
Low Range
4 to 6 seconds
High Range
9 to 11 seconds
Minimum Travel Speed
Forward Motion
11 km/h
(600 ft/min)
Reverse Motion
11 km/h
(600 ft/min)
Times
for
forward
and
reverse
through
the
30.5 m
(100 ft) timing trap must match within one second.
10-62
