| 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 in good condition. The battery checking method is described in the
section "Battery".
The battery that is used to test the output current should be
the 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, because 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 is measured at 0V, 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 starts up, the charging current quickly
drops. Therefore, the above operation must be done quickly to read the
maximum current value correctly. |
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|
| (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, it may be difficult to obtain the nominal output
current. 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. |
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Description and Operation
Alternator Description and Operation