Appendix
Operation Manual -
SP 30570
revDate
Example 2—Checking your hydraulic pumps
To determine whether your pumps are still in good
working condition, use the output chart and a flow
meter. Test one pump at a time, multiply the readings
by 2, and chart the result. You must multiply the
readings because the chart is based on the output of
two pumps, but we are only testing one at a time.
To test your pumps:
• Be sure you are using the chart that applies to
your unit.
• Select the proper gear for pumping (found on
the information plate mounted in the cab).
• Set the pump speed (input drive shaft) RPM.
Pump speed information is found on line 16 of
the Delivery Inspection Report which arrived
with your unit when it was new. A difference
of even a few RPM will give you a bad read-
ing. Check the RPM of the drive shaft with a
digital tachometer if one is available.
• Know how to use your flowmeter. Read the
instructions that came with it, and remember
that a flowmeter must be calibrated periodi-
cally.
• Make two copies of the output chart so you
don’t ruin your original. You need one chart for
each pump tested.
Read the flow at 0 bar, 100 bar, 150 or 200 bar, 250 bar,
and 300 bar. Also, document the breakpoint. The
breakpoint is where the flow drops off rapidly. You will
be able to notice it on the flowmeter. If you think it
would be helpful, copy the chart below. Check which
reading you used (150 or 200 bar). The breakpoint will
be very close to either 150 or 200 bar, so it is not
necessary to take both readings. The breakpoint
specification is shown on each output chart.
As an example, we’ll assume that we have just taken
the following readings:
Liters/min
(read on meter)
Tota l
(for plotting)
0 bar
100 bar
breakpoint
150 or 200 bar
250 bar
300 bar
x 2
x 2
x 2
x 2
x 2
x 2
Liters/min
(read on meter)
Tota l
(for plotting)
x 2
x 2
x 2
x 2
x 2
x 2
1st Pump 2nd Pump
Breakpoint
specification
breakpoint
000032.eps
Liters/min
(read on meter)
Tota l
(for plotting)
0 bar
100 bar
breakpoint
150 or 200 bar
250 bar
300 bar
x 2
x 2
x 2
x 2
x 2
x 2
Liters/min
(read on meter)
Tota l
(for plotting)
x 2
x 2
x 2
x 2
x 2
x 2
1st Pump 2nd Pump
Breakpoint
specification
breakpoint
199
196
194
169
138
117
178
398
392
388
338
276
234
178
000031.eps
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