Piper CHEROKEE WARRIOR PA-28-151 1995 Maintenance Manual page 429

PIPER CHEROKEE WARRIOR SERV I C E M A N U A L
11-69 LAMAR 28 V0LT REGULATOR OVERVOLTAGE CHECK
The Lamar regulator has an incorporated overvoltage relay. To check relay operation use the same test
connections as testing the regulator, except connect the bulb across the RED and BLUE wires. (Refer to figure
11-48.) Test as follows:
a. While monitoring both the voltmeter and the light bulb, increase voltage to circuit slowly to 32
volts.
b. After a slight delay, the bulb will light.
c. If overvoltage control fails to operate at 32 Vdc, it must be replaced.
11-70 . STARTING MOTORS. (PRESTOLITE and ELECTROSYSTEMS)
It is the user's responsibility to refer to the applicable vendor
publication when servicing or inspecting vendor equipment
installed in Piper aircraft, .
11-7 1. DESCRIPTION. (See Figure 11-49.)
The PA28-151, Wa r r i o r, and the PA-28-161, Warrior II, are equipped with a 12 Vdc starter; the PA - 2 8 -
161, Warrior II has a 24 Vdc starter. The following description and procedures apply to both the 12 Vdc and 24
Vdc starters.
The gear reduction starting motor has six major components: the commutator end head assembly, the
armature, the frame and field assembly, the gear housing, the pinion housing, and the Bendix drive assembly.
11-72. OPERATION.
When the starting circuit is energized, battery current (12 or 24 Vdc, as applicable) is applied to the
starting motor terminal. Current flows through the field coils, creating a strong magnetic field. At the same time,
c u rrent flows through the brushes to the commutator, through the armature windings to ground. The magnetic
force created in the armature, combined with that created in the field windings, begins to turn the armature.
The gear cut on the drive end of the armature shaft extends through the gear housing, and is support-
ed by a roller bearing. The gear mates with the teeth of the reduction gear that drives the Bendix shaft. The
shaft is keyed to the reduction gear. The Bendix drive is held in position on the shaft by a spiral pin. The shaft
is supported in the gear housing by a closed end roller bearing and in the pinion housing by a graphitized bronze
bearing.
When the armature turns the reduction gear, the Bendix drive pinion engages with the flywheel ring
gear by inertia and action of the screw threads within the Bendix sleeve. A detent pin fits in a notch in the
screw threads and prevents disengaging if engine fails to start when the starting circuit is de-energized.
When the engine reaches a predetermined speed, centrifugal action forces the detent pin out of the
notch in the screw shaft and allows the pinion to disengage from the flywheel.
Revised: February 28, 1995
WARNING
2F22
Island Enterprises
ELECTRICAL SYSTEM