Piper Dakota Maintenance Manual page 189

CHART 2401. TROUBLESHOOTING (ALTERNATOR) (cont)
Trouble
Field circuit breaker trips.
(cont.)
Ammeter indicates 60 amps
at l400 rpm and above,
ALT annunciator light on.
Battery installed with re-
versed polarity.
PIPER AIRCRAFT
PA-28-236
MAINTENANCE MANUAL
Cause
Short circuit in field winding
of alternator.
Short to ground in alterna-
tor output wiring.
Battery charged backwards.
1I4
Remedy
Disconnect field wiring at
terminal of alternator. Turn
on master switch. Reset
breaker and if breaker fails
to retrip, this isolates short
circuit to field of alternator
itself. Check brush holders
for shorting against frame. If
there are no obvious signs of
a physical short circuit at field
terminal or brush holder, re
place alternator. (Note: Inter
mittent short circuit.)
—WARNING—
Turn magneto switch to OFF
before turning propeller.
Internal short circuiting of
the field can occur at various
positions of the rotor, there
fore, reconnect field reset
breaker, pull propeller slowly
by hand turning alternator
rotor through 360° of travel.
Observe circuit breaker for
signs of tripping.
Check condition of teflon
insulators on feet of diode
heat sink. When the mount
ing screws are overtorqued,
they can cut through insula-
tors causing a short-to-
ground. Check other wiring
for chafing, etc.
Remove battery and reinstall
with correct polarity.
24 - 02 - 00
Page - 24 - 05
Reissued: August 1, 1986