PGP/PGM 300 Series
Service Manual HY09-SM300/US
13
Parker Hannifin Corporation
Gear Pump Division
Youngstown, OH
Recommended
Test Procedure
Make certain that there is an adequate supply of oil for
the pump; at least one gallon of oiI for each gpm of
pump capacity.
If one section of a tandem pump is being tested,
make sure that all other sections not being tested
are adequately supplied with oil. If any of the other
sections run dry, or if plugs are left in ports, serious
and permanent damage will result.
The oil should be a good quality hydraulic oil rated at
150 SSU at 100° F., with the oil temperature held at
120° F. plus or minus 50° F. (Test procedures are
described in detail in SAE handbooks; see Hydraulic
Power Pump Test Procedure, SAE J745c.)
The feed line must be of adequate size with no more
than 5" mercury vacuum adjacent to the pump inlet. As
a rule, the feed line must provide a feed flow velocity
not in excess of 8 feet per second.
Feeding hot oil into a cold pump may cause the pump
to seize. Jog the pump by momentarily starting and
stopping repeatedly the driving engine or motor to
gradually equalize pump and oil temperatures.
Run the pump at least two minutes at no load and
moderate speed (not over 1500 rpm). If the pump
becomes excessively hot, shut down immediately and
locate the problem source.
Gradually increase pressure on pump, in 500 psi
increments until the desired test pressure has been
reached. This should take about five minutes.
Delivery should run close to rated catalog performance
figures, which are averaged from testing several
pumps. A 5% lower reading may be used as a rated
minimum if new or relatively new parts have been
used. When rebuilding the pump with parts from the
original pump, which, while worn, appear satisfactory
for reuse, a 10% or 15% lower reading may be
permitted, depending on the performance expected
from the equipment. One's own experience will prove
the best guide here.
Many repairmen measure the output at normal
operating speed and at zero pressure, then again at
1000 psi (or the operating pressure of the equipment)
and allow a volume decrease approximating the listing
below. It is a suggested reference only which makes
allowance for reused parts.
At test speeds other than 1800 rpm, gpm delivery will
vary almost proportionately, but the same (drop-off)
figures should be used.
Be sure to run the pump in the direction for which it
was designed and built. Driving the pump in the wrong
direction will build up pressure behind the shaft seal,
damaging it and necessitating replacement.
After completing testing procedures, the pump is
ready for installation and immediate duty operation
on equipment. Again, it must be remembered that
to prevent seizure, hot oil must not be fed into a
cold pump.
