Hydraulic Pump Motor Characteristics; With Gear Unsafe Light On, Pump Operates On And Off; With Gear Unsafe Light On, Pump Motor Circuit Breaker Opens - Piper PA-44-180 SEMINOLE Maintenance Manual

CHART 2902. TROUBLESHOOTING HYDRAULIC SYSTEM (cont.)
Trouble
With gear selector down and
three green lights on, gear unsafe
light comes on intermittently or
continuously.
With gear selector down and
three green lights on, pump
motor circuit breaker opens.
With gear unsafe light on, pump
operates on and off.
With gear unsafe light on, pump
motor circuit breaker opens.
CHART 2903. HYDRAULIC PUMP MOTOR CHARACTERISTICS
ELECTRICAL CHARACTERISTICS
Voltage
Rotation
Polarity
Operating Current
Operating Time
Overload Protection
Automatic Reset Time
Location, Automatic Reset
M E C H A N I C A L
C H A R A C T E RI STICS
Bearings
End Play, Armature
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
Cause
Shorted gear up solenoid.
Shorted gear up solenoid.
Shorted gear down solenoid.
Shorted gear down solenoid.
P R E S TOLITE - HYC5005
14 VDC
Reversible
Negative ground
75 amps, max. at 14 volts (both
rotations)
12 seconds max. with a current
load of 75 amperes at 77 ° F.
Thermal circuit breaker
12 seconds, max.
Commutator end head of motor
Absorbent bronze (Drive end
bearing in upper pump and
valve assembly casting)
Steel ball (Thrust, between
c o mmutator end head and end
of armature shaft)
0.005 inch, minimum (Adjust by
selection of thrust washers on
drive end of armature shaft)
2C6
Remedy
Replace solenoid.
Replace solenoid.
Replace solenoid.
Replace solenoid.
OILDYNE - PIPER P/N 481 879
14 VDC
Reversible
Negative ground
18 amps, max at 14 volts(both
rotations)
5 - 10 seconds with a current load
of 100 amperes at 77° F.
Thermal circuit breaker
12 seconds, max.
Commutator end head of motor
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Page 29-11
Revised: June 20, 1995
29-02-00