2. |
Output Current Test
This test determines whether or not the alternator gives an output current
that is equivalent to the normal output.
(1) |
Preparation
a. |
Prior to the test, check the following items and correct
as necessary.
Check the battery installed in the vehicle to ensure
that it is good condition. The battery checking method
is described in the section "Battery".
The battery that is used to test the output current
should be one that has been partially discharged. With
a fully charged battery, the test may not be conducted
correctly due to an insufficient load.
Check the tension of the alternator drive belt. The
belt tension check method is described in the section
"Inspect drive belt".
|
b. |
Turn off the ignition switch.
|
c. |
Disconnect the battery ground cable.
|
d. |
Disconnect the alternator output wire from the alternator
"B" terminal.
|
e. |
Connect a DC ammeter (0 to 150A) in series between the
"B" terminal and the disconnected output wire. Be sure
to connect the (-) lead wire of the ammeter to the disconnected
output wire.
• |
Tighten each connection securely, as
a heavy current will flow. Do not rely
on clips.
|
|
|
f. |
Connect a voltmeter (0 to 20V) between the "B" terminal
and ground. Connect the (+) lead wire to the alternator
"B" terminal and (-) lead wire to a good ground.
|
g. |
Attach an engine tachometer and connect the battery
ground cable.
|
h. |
Leave the engine hood open.
|
|
(2) |
Test
a. |
Check to see that the voltmeter reads as the same value
as the battery voltage. If the voltmeter reads 0V, and
the open circuit in the wire between alternator "B"
terminal and battery (+) terminal or poor grounding
is suspected.
|
b. |
Start the engine and turn on the headlamps.
|
c. |
Set the headlamps to high beam and the heater blower
switch to HIGH, quickly increase the engine speed to
2,500 rpm and read the maximum output current value
indicated by the ammeter.
• |
After the engine start up, the charging
current quickly drops. Therefore, the
above operation must be done quickly
to read the maximum current value correctly.
|
|
|
|
(3) |
Result
a. |
The ammeter reading must be higher than the limit value.
If it is lower but the alternator output wire is in
good condition, remove the alternator from the vehicle
and test it.
Limit value : 60% of the voltage rate
|
• |
The nominal output current value is
shown on the nameplate affixed to the
alternator body.
|
• |
The output current value changes with
the electrical load and the temperature
of the alternator itself.
Therefore, the nominal output current
may not be obtained. If such is the
case, keep the headlamps on the cause
discharge of the battery, or use the
lights of another vehicle to increase
the electrical load.
|
• |
The nominal output current may not be
obtained if the temperature of the alternator
itself or ambient temperature is too
high. In such a case, reduce the temperature
before testing again.
|
|
|
b. |
Upon completion of the output current test, lower the
engine speed to idle and turn off the ignition switch.
|
c. |
Disconnect the battery ground cable.
|
d. |
Remove the ammeter and voltmeter and the engine tachometer.
|
e. |
Connect the alternator output wire to the alternator
"B" terminal.
|
f. |
Connect the battery ground cable.
|
|
|