Overhaul Of Alternator; Alternator System; Bench Testing Alternator; Rotor Field Coil Current Draw - Piper Dakota Maintenance Manual

OVERHAUL OF ALTERNATOR

When repairing alternator, complete disassembly may not be required. In some cases it will only be
necessary to perform those operations which are required to effect repair. However, in this section, complete
overhaul is covered to provide detailed information on each operation. In actual service practice, these
operations may be used as required.
ALTERNATOR SYSTEM (CHRYSLER)

BENCH TESTING ALTERNATOR

ROTOR FIELD COIL CURRENT DRAW (figure 21 3)
l. Connect jumper wire between one field terminal of alternator and positive terminal of a fully charged
battery.
2. Connect test ammeter positive lead to other field terminal of alternator and test ammeter negative lead
to battery negative terminal.
3. While watching test ammeter, slowly rotate alternator rotor by hand.
a. Field coil draw should be 4.5 to 6.5 amperes at l2 volts.
b. A low rotor coil draw is an indication of high resistance in the field coil circuit (brushes, slip rings,
or rotor coils).A higher rotor coil draw indicates a possible shorted rotor coil or grounded rotor.
c. No reading indicates an open rotor or defective brushes.
TESTING ALTERNATOR INTERNAL FIELD CIRCUIT
To test alternator internal field circuit for a short circuit to ground, proceed as follows:
1. Remove ground brush and place one test probe of a ll0-volt test lamp to field terminal. Attach
remaining test probe to a machined surface at one of the alternator end shields. Test lamp should not
light. (Refer to figure 24~.)
2. If test lamp lights, proceed as follows:
a. Remove insulated brush assembly.
b. Remove three bolts and separate two end shield assemblies.
PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL
1I11
24 - 32 - 00
Page - 24 - 12
Reissued: August 1, 1986