Stator Checks; Diode Checks - Piper PA-24 Comanche Service Manual

FIGURE 9.11. CHECKING ROTOR
"..-.., I
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OHMMETIJI
lOt SHOITS ANO 0l'INI1
rectifyina diades.
b. Stator Checks - To ch.ck the stator
wiadiA,s, remove all three stator lead attachin,
nuts (Fiaun 9-18). and th.a .. parat. the stator
..sembly &om the ead fr.... The fit between
Itstor frame IIld end frame is not tiaht. and the
two can
be ..
pu.ted euUy.
The Itator willdilllS may be cheeked
with
I
lID-volt test l. .p or
III
ohmmet.r. If
the lamp Hltns. or if the meter readinl is low
when cocmected from any stator Ie.:! to the
f,llllle. the willdinlS an pounded. If the lamp
fails to liaht. or if lIleter readiDl is hith when
suee...ively connected between each pair of
stator leads. the windines are open (FilUre
9-19).
A short eircuit ill the stltor windinls is
difficult to locate without
laborato~
test eqUip-
ment due to the tow resistance of the windinls.
However, if ,U other electrical checks are
normal and the lenerator fails to supply rated output. ahorted atator wmdinp are indicated.
e. Diode Cheeks - Each diode may be checked electrically for a sborted or open condition.
Anyone of the methods outlined below may be used.
Ohmmeter Method: One method of checking diodes is to u.e an ordinary ohmmeter commonly
found in service stations. The lowest ranle scale on the ohmmeter should be used. and the
ohm~
meter should have a IV, volt cell. To determine the cell voltllp.
tum
the selector to the lowest
scale. and then connect the ohmmeter lead. to a voltmeter. The voltmeter
will
indicate the cell
voltace.
PIPER COMANCHE SERVICE MANUAL
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LEAD AnACHING NUTS
SlUSH HOLDEI
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FIGURE '.18. SLIP RING El"ID FRAME
FIGURE 9.19. CHECKING STATOR
ELECTRICAL SYSTEM
ISSUED: 8/18/72
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