13
Parker Hannifin Corporation
Gear Pump Division
Youngstown, OH
Recommended
Test Procedure
To be sure that there is an adequate supply of oil for
the pump, maintain at least one gallon of oil 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 the plugs are left in the 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 5°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.
Hot oil must not be fed into a cold pump. It may seize.
Jogging the pump may prevent seizure.
Operate the pump at least two minutes at zero
pressure and at moderate speed (not over 1500 rpm)
If the pump becomes hot to touch, it is binding and
may seize. This doesn't happen often, but if it does,
the pump will have to be disassembled and rebuilt,
with extra care taken to remove burrs and to assure
freedom from binding.
Gradually increase pressure on the pump, until the
desired test pressure has been reached. This should
take about five minutes.
Pump output flow 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. Worn parts, which meet the guidelines for
acceptable wear, (See page 9) may be used to
rebuild the pump, however, the performance
rating may decrease. (A 10-15% lower rating can
be expected.)
Many repairmen measure the output at normal
operating speed and at zero pressure, then again at
1000 psi (or the operating pressure of the equip-
ment), and allow a volume decrease approximating
the listing below. This is a suggested reference, only
which makes allowance for re-used parts.
PGP030/050 pumps are generally tested to 2000 psi
maximum.
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.
Since it is rarely feasible to test motors on
dynamometers, the practical procedure is to test them
as pumps, running complete testing procedures in
each direction.
After completing testing procedures, the pump is
ready for installation and immediate duty operation
on the equipment. Again, it must be remembered
that to prevent seizure, hot oil must not be fed into
a cold pump.
Service Manual HY09-SM030/031/050/051/US
Recommended Test Procedures
Series PGP 030/031 Series PGP 050/051
