Piper Comanche PA-24 Service Manual page 704

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PIPER COMANCHE SERVICE MANUAL
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FIGVRE 9-27n. BRVSH INSTALLATION FIGVRE 9-270. INTERNAL WIRI:-IG
DIAGRAM
9-01j Precautions. The following precautions are to be observed when testing or sen iCIng the ekctnc,l
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stem
a Disconnect the battery before connecting or disconnecting test instruments 'except \oltmeter) or
before remO\ing or replacing anv unit or winng Accidental grounding or shorting at the regula tor. a Iterna t .
ammeter or accessories. will cause "\ere damage to the units and or wiring •
b The alternator must not be operated on open circuit with the rotor winding energi/ed
c Do not attempt to polarize the alternator.
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polarization is required An\ attempt to do
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result in damage to the alternator. regulator or circuits
d Grounding of the alternator output terminal may damage the alternator and or circuit and
components
e R,,·ersed battery connections may damage the rectifiers. wiring or other components of the
charging system Battery polarity should be checked with a voltmeter before connecting the batten Mo,t
aircraft are negative ground
f If a booster battery or fast charger is used. its polarity must be connected correct" to pre\ent
damage
to
the electrical system components
9-0 I k Alternator Nomenclature.
a. Bearings These units have a sealed ball bearing at the driw end and a two-piece roller bearing"t
the slip ring end The inner race is pressed onto the rotor shaft and the rest of the bearing is in the ,lip ringend
head When the unit is assembled. the inner race aligns with the bearing. When the bearing is replaced. the ne"
inner race must be installed on the rotor shaft.
b Lubrication, The slip ring end bearing should be lubricated whenever the alternator is dis-
assembled The bearing should be thoroughly cleaned and repacked with Shell AI\ania !\o. 2 or an equi\alent
bearing lubricant The cavity behind the bearing should be packed one-third to one-half full" ith the same
lubricant
c Brushes. These units have a separate brush holder assembly that is installed after the
alternator has been assembled. The brush holder has a small hole that intersects the brush
ISSt;ED: 8/18/72
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ELECTRIC AL SYSTEtt