Piper Comanche PA-24 Service Manual page 708

PIPER COMANCHE SERVICE MANUAL
g. The ala:mamr Ibould be ill
aoocI
COadiaoll &lid capable of
prodllciDfl
full ""cput. ... eI the
ai=Daarr cIrift belt ...... be adjustccI tipt
"""up.
to
P""'CIlt s1iPPIIC- lid ..
ED
panpapb 9-91 for
methocls
of
cbcckiIl,
belt lCIIIiollI.
h. The banery mWlt be ill ,oocI cOI1e1itiol1 ancl should be fully chargee!.
i. The voltmeter al1cl ammeter should be of the best quality aacI should be accurate.
j. A carbon.pile connectee! ac..,.s the battery sy be ... ecI to load the chargil1& circuit while
testing tbe regulator.
9-61q.
r.sti ..
R.,ulatar.
a. Tbe proceelure for tasli", the .. ,ulator, wbetber
OIl
the airpl ... e or on the test bench,
resins the same. COl1l1ect test IDOters
as
showl1 ill FilUfe
9-2iq.
0. All cizcllit cODDections ah""ld be clean al1cl liaht. This include. the teSt ilIItruMent con·
nectioas which must
mot
come Lool. or open. the charlirll circuit at aa.y time whlle the system
is operating.
c. The voltmeter _Ul 110t indicate the true regulator seninl until the regulator bes been
operating in the charging system or on the test bel1ch for at least one maute. at a charge rate of
hom 10 to 15-amperes.
d. Connect the voltmeter al1cl the am_ter as .hown in Figure 9-27q. Start the engine ar.d
aeljust its speeel to obtain 3,000 to 4,000 alternator RPM. Tum on accessories as ,,"eded to es·
tablish 10 to 15-ampent electrical load, or use a carbon.pile across the
battery
to obtain this
charge rate.
e. After
one
minute operatilll time, cbeck the reaulator operating voltage
as
indicatee! by the
voltmeter. Refer to Alternator Service Test Specifications. paragraph 9-611, for the correct oper-
ating voltap. The operatinl yo1taae is sbowD. for the ambient temperature in which the tegwiltor
is operatiDg.
f. If the voltMeter reading il1clicatas that the operating voltaae is not within limits. lift the
plastic plug from top of regulator anel adjust the voltage to tbe desired value. Replace the plug
after adjustment. Before condemrung
th~
regulator, recheck the alternator and. the battery; making
sure that they are in good condition. Recheck
all circuit connections and all wiring for un-
wantee! re.istance (voltage drop te.t). Recheck
the voltmeter for accuracy and repeat the
entire operating test.
9-<; 1r. Acli.stln, R.,.latar.
a. Adjustment: These units have an ex-
ternal adjustment located UDder the plaatic
plug o. top of the regulator. The regulator has
an adjustmel1t spread ral1ging (rom 13.O-volts
to 15.0 volts. Output
is
increased bytuming the
adjustment clockwise.
b. Operalll1i Voltage: The
regulators~ould
be
adjusted to 14.2-volts when controlli", a
load of 10 to lS .... p. after one minute opere
anon. Tbese units are not affected
by
ambient
te:nperatures. The volt:neter must be conneC'!:ed
from the "I" or switch terminal to ground.
ELECTRICAL SYSTEM
3
C8
FIGURE 9-27q. TESTING REGULATOR