Keep
these points
in
mind
when
testing or servicing the
flywheel alternator:
I
1.
Be sure engine is being run long enough and fast
enough to recharge battery after each start. Charging
system tests requirea full charged battery. Alternator
output is reduced in direct proportion toengine rpm.
Also, power required for accessories reduces power
available to recharge battery.
2.
The regulator-rectifier has built in protection against
open circuits or short circuits on the alternator
output (e+) terminal. Either condition will cause the
regulator-rectifier toshut
off
and appear as
if
it is not
functioning. Prior to checking the regulator-rectifier,
check all wiring between the regulator-rectifier B+
terminal and the battery positive
(+)
terminal to
assure it is free of open circuits, resistances or short
circuits. Also,
if
the battery is extremely discharged
it may have insufficient power to “turn on” the
reg ulator-rectifier.
3.
Be sure regulator-rectifier plug (connector) is in-
serted properly. Plug must bottom in receptacle; this
eliminates any resistance due to a poor connection.
Keep clean and tight.
4.
Make sure alternator stator leads are not shorted
together.
5.
Be sure regulator-rectifier has a good ground
connection. Mating surface for mounting must be
clean and fasteners tightened properly.
6.
Never reverse the battery leads.
When the engine is running between
1800
to
2600
rpm,
observe the panel ammeter (if not already equipped,
connect a test ammeter). If no charging is evident,
proceed with the
A/ternator
Output
Test.
ALTERNATOR OUTPUT TEST
Use a volt-ohmmeter, such as the Simpson
270,
when
testing the charging system.
1.
Check battery voltage with unit not running. If not
within specifications(Tab1e
1)
charge battery before
proceeding to step
2.
2.
With the engine running, check the battery terminal
voltage (regulator output) using a DC voltmeter.
Voltage output should be within thevalues specified
in Table
1.
If
voltage is greater than specified,
replace regulator-rectifier assembly.
If
voltage is
less than specified, proceed to step
3.
3.
Examine all wires for loose, corroded, or broken
connections. Check fuses. Repair as needed to
assure continuity between the regulator-rectifier B+
terminal to battery positive
(+)
terminal.
Also
check
ground path from battery negative
(-)
terminal to
regulator-rectifier case. Make sure ground con-
nections are clean and secure.
If
battery voltage
remains low with engine running, proceed to step
4.
4.
Disconnect both ACstator leadsfrom the regulator-
rectifier and test the AC voltage at the stator leads
with engine running.
If
AC voltage reads more or
less than specified in Table
1,
proceed to step
5.
If
AC voltage is as specified but
DC
voltage is low,
replace regulator-rectifier.
5.
Use the
Rxl
scale on the ohmmeter for detecting an
open or ground in the stator (unit not running).
Disconnect both AC stator leadsfrom the regulator-
rectifier. Connect one ohmmeter test lead to a stator
lead, connect the other test lead to ground. Reading
should show an open (no continuity).
If
it doesn’t, the
stator must be replaced.
If
reading shows no con-
tinuity, measure the resistance of the stator winding
by connecting one ohmmeter lead to each lead
coming from the stator. Refer to Table
1
for resist-
ance specifications.
If
resistance is not as specified,
replace stator.
If
stator resistance readings are as
specified and windings are not shorted or open, low
AC voltage may be due
to
loss
of magnetism. If
so,
blower wheel assembly must be replaced.
8-5
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