Bench Testing The Alternator; Field Current Draw - Piper Cherokee Six Service Manual

PIPER CHEROKEE SIX SERVICE MANUAL
2612
Alligator
Clips
8A Landing Lights as required
Figure
10-3. Lamp-Bank
Load
10-5.
BENCH TESTING THE ALTERNATOR.
10-6.
FIELD CURRENT DRAW. Connect a test ammeter
in series between a 12-
volt battery positive postand the alternator
field terminal.
(Refer to Figure 10-4.)
Connect a jumper wire to a machined
surface on one of the alternator
end
shields (ground) and to the negative
battery
post. The reason
for connecting
to
the machined
surface is to ensure a good electrical
connection.
The end shields
are treated
to oppose corrosion.
The material
used to treat
the end shields is
not a good electrical
conductor.
Observe
the ammeter
to determine
the current
flowing through the rotor
coil and connected circuit
and record
the amount.
Slowly rotate
the rotor
with
the pulley while watching the meter.
The current
will be a little less while ro-
tating the rotor
than when stationary.
However, if the slip rings are clean and
the brushes are making good contact,
the reading should be fairly even. A
AMMETER
slight fluctuation
will be normal due to
variation
in turning speed when oper-
ated by hand.
The current
draw should not be
less than 2.3-amperes nor more than
2
.7-amperes.
A reading
of less than
2.3-amperes
indicates high resistance
due to poorly soldered
coil leads at the
12V BAT.
slip rings,
dirty, oily slip
rings
or
poor brush contact.
A reading
higher
than
2
.7-amperes
indicates
shorted
Figure
10-4. Checking Field Current
- coil windings.
ELECTRICAL
SYSTEM
Issued: 8/17/72
3A22