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Charging Voltage Test
1.
Turn
keyswitch
off
on marine engi-
nes or
discon-
nect
the
oil
pressure switch
wire on genera-
tor sets.
(+)
2.
Disconnect
cable from
positive
terminal of
battery and
connect an
ammeter in
series
between
the
cable
and
positive
(+)
terminal of the
battery.
---0';----+---.....
to
Ltai
Battery
-:-
3.
Connect a voltmeter between terminal
(L)
of alternator and
ground.
Check to ensure that the voltmeter reading is zero.
If
the
pointer
of
the
voltmeter
deflects
(a
voltage
present),
a
defective alternator or wiring is suspected.
4.
Turn keyswitch on or connect the oil pressure switch terminal
to ground,
but do not start the engine.
The voltmeter reading
should be considerably lower
than the battery voltage.
If the
voltmeter
reading
is much
the
same
as
the
battery voltage,
a
defective alternator is suspected.
5.
With the ammeter terminals short-circuited, start the engine.
CAUTION:
MAKE SURE THAT WHEN THE ENGINE IS STARTED, NO STARTING CURRENT IS
APPLIED TO THE AMMETER.
6.
Remove
the
short circuit across
the ammeter
terminals
and
increase the engine speed
immediately to approximately 2,000 to
3,000 rpm.
Take the ammeter reading.
7.
If
the ammeter
reading
is SA or
less,
take
the
voltmeter
reading without changing the engine speed
(2,000 to 3,000 rpm).
The reading is the charging voltage.
NOTE:
Since the electronic voltage regulator is a temperature
compensation type,
the charging voltage varies with temperature.
Therefore, the temperature around the rear bracket of the alter-
nator must be measured and the charging voltage corrected to the
temperature.
Description
Charging voltage
Temperature compensation
gradient
100
Standard value
14.4 +0.3V at 20·C (6S·F)
-O.lV/lO·C (sO·F)
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