Piper CHEROKEE WARRIOR PA-28-151 1995 Maintenance Manual page 368

PIPER CHEROKEE WARRIOR SERV I C E M A N U A L
11-1. INTRODUCTION.
This section contains instructions and schematics for correcting difficulties which may arise in the
operation of the electrical system in the aircraft.
The instructions are organized so the mechanic can refer to: Description and Principles of Operation
for a basic understanding of the various electrical systems; Troubleshooting for a methodical approach in locating
the difficulty; Corrective Maintenance for removal, repair, and installation of components; and adjustments
and tests for operation of the repaired system. Schematics for the individual systems are located at the end of
this section. For information concerning electronic equipment, refer to Section XII Electronics.
When servicing or inspecting vendor equipment installed in
Piper aircraft, it is the user's responsibility to refer to the
applicable vendor publication.
11-2. DESCRIPTION.
a. Warrior/Warrior II (S/N's 28-7415001 and up, 28-7716002 and up, 2816001 thru 2816109)
Electrical power is supplied by a 14 volt, direct current, negative ground electrical system. A 12
Vdc battery is incorporated into the system to furnish power for starting and as a reserve power source in case
of alternator failure.
The electrical generating system consists of an engine driven 60 ampere alternator. A solid state
voltage regulator maintains the system bus voltage at 14 volts. Also incorporated is an overvoltage relay
which prevents damage to electrical and avionic equipment in case of regulator malfunction. The loads from
the elec trical bus system are protected by manual reset type circuit breakers mounted on the lower right hand
side of the instrument panel.
The master switch must be on before any electrical equipment will operate. The master switch
controls the battery relay and field circuit. The switch is a double pole single throw type.
The lighting system for night time operation is optional equipment and consists of a landing light,
anti-collision lights and navigation lights.
b. Warrior III (S/N's 2816110 and up)
The electrical system is a 28 volt, direct current, single wire, negative ground system. All electrical
equipment is grounded to the metal structure of airplane. The structure takes the place of a second wire. A 24
Vdc battery is incorporated into the system to furnish power for starting and as a reserve power source in case
of alternator failure.
The battery and 60 amp alternator are connected to the bus bar that powers all electrical equipment,
except the starter, which receives its power direct from battery. The battery relay and alternator field circuit
are controlled by independent rocker type master (BATT MASTR) and alternator (ALTR) switches located on
the instrument panel. The alternator switch (ALTR) may be used to turn OFF the alternator field in the event
of alternator failure. A warning light (ALTERNATOR INOPP
illuminate if the alternator fails to produce current, accompanied by a zero indication on the ammeter. A low
voltage warning light (LOW BUS VOLTAGE) on the annunciator panel will illuminate when alternator output
is lost and the system is drawing power from the battery alone. The master switch (BATT MASTR) must be ON
before any elect r ical equipment will operate.
Revised: February 28, 1995
SECTION XI
ELECTRICAL SYSTEM
WARNING
2e16
2D9
Island Enterprises
2e16) on the annunciator panel will
ELECTRICAL SYSTEM