b. The alternator must not be operated on an open circuit with the rotor winding energized.
c. Do not attempt to polarize the alternator. No polarization is required. Any attempt to do so may result in
damage to the alternator, regulator or circuits.
d. Grounding of the alternator output terminal may damage the alternator and/or circuit and components.
e. Reversed battery connections may damage the rectifiers, wiring or other components of the charging
system. Battery polarity should be checked with a voltmeter before connecting the battery. This aircraft is
negative ground.
f. If a booster battery or fast charger is used, its polarity must be connected correctly to prevent damage to the
electrical system components.
Il-I5. ALTERNATOR NOMENCLATURE.
a. Bearing: This unit has a sealed ball bearing at the drive end and a two piece roller bearing at the slip ring
end. The inner race is pressed onto the rotor shaft and the rest of the bearing is in the slip ring end head. When
the unit is assembled, the inner race aligns with the bearing. When the bearing is replaced, the new inner race
must be installed on the rotor shaft.
b. Lubrication: The slip ring end bearing should be lubricated whenever the alternator is disassembled. The
bearing should be thoroughly cleaned and repacked with Shell Alvania No. 2 or an equivalent bearing lubricant.
The cavity behind the bearing should be packed one-third to one-half full with the same lubricant.
c. Brushes: These units have a separate brush holder assembly that is installed after the alternator has been
assembled. The brush holder has a small hole that intersects the brush cavities. Use a pin or a piece of wire, as
shown in Figure 11-15 to hold the brushes in the holder during assembly. Remove the pin after the brush holder
retaining screws have been tightened. Make a continuity check to be sure the brushes are seated against the slip
rings.
d. Drive Pulley: Torque the drive pulley retaining nut to 35 foot-pounds (minimum) to 40 foot-pounds
(maximum).
Figure 11-15. Brush Installation
Figure 11-16. Internal Wiring Diagram
371
PIN
1 FLD 2
END VIEW
SIDE VIEW
C326
F
STATOR
WINDINGS
-
+
-
+
-
+
AUX
OUTPUT
ROTOR
WINDINGS
BRUSHES
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
ELECTRICAL SYSTEM
2D7
