CHART 2903. CHARACTERISTICS, HYDRAULIC PUMP MOTOR
Electrical Characteristics:
Voltage 14 DC
Rotation Reversible
Polarity Negative ground
Operating Current 18 amps, max. at 14-volts (both rotations)
Operating Time 5 to 10 seconds with a current load of
100 amps at 77°F.
Overload Protection Thermal circuit breaker
Automatic Reset Time 12 seconds, max.
Location, Automatic Reset Commutator end head of motor
Mechanical Characteristics:
Bearings Absorbent bronze
(Drive end bearing in upper pump and
valve assembly casting.)
Steel ball
(Thrust, between commutator end head
and end of armature shaft.)
End Play, Armature .005 inch, min.
(Adjust by selection of thrust washers on
drive end of armature shaft.)
H. Should it be necessary to check the pump motor, first connect the ammeter in the electrical circuit
with the positive terminal of the meter to the black lead and the negative terminal of the meter to
negative terminal of the DC power supply.
I. Connect the blue lead to the positive terminal of the power supply. With the high pressure
indication within the 1600 to 2000 psi range (2000 to 2500 psi on Piper P/N 67509-2) on the
pressure gauge, the ammeter should read between 35 to 60 amperes. Disconnect the electrical lead.
J. Connect the green lead to the positive terminal of the power supply. With the high pressure
indication within the 500 to 800 psi range, the ammeter should read between 15 to 35 amperes.
—NOTE—
In the event that any of the various tests do not perform
s a t i s f a c t o r i l y, the pump assembly should be overhauled or
replaced.
K. Connect the green lead to the power supply to drop pressures before disconnecting the hydraulic
lines.
29-10-06
Page 29-21
Revised: November 6, 1979
2C15
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL