04-7
Charainrr System
04-7
DIAGNOSIS AND TESTING (Continued)
Regulator’ Bypass Test
Perform this test if the Output Voltage Test indicates less
than 13.6 volts at light load.
1. Key OFF.
2.
Disconnect the field lead from the “F” terminal.
3. Connect a jumper from the “F” terminal to the “R”
terminal.
4. Start the engine.
CAUTION: Be sure to keep the rpm low, as an
unregulated generator can produce voltage high
enough to cause damage.
5. With the engine running at idle, check the output
voltage.
GENERATOR
VOLTMETER
l
If the output voltage is still low, the problem is in
the generator.
l
If the output voltage rises above 13.6 volts with the
regulator bypassed, check the regulator circuit for
low output (although the problem may still be partly
or entirely in the generator). Possible generator
problems include:
- Defective output or field diodes.
- Excess resistance in the field circuit, which
includes the regulator.
- Excess resistance in the charging circuit
external to the generator.
Key-Off Check
1. Key OFF.
2. Remove the jumper between the “R” and “F”
terminals, if present.
3.
Connect the field lead to the “F” terminal, if it is not
already corrected.
4. Check the voltage at the “R” terminal. If any voltage is
present, it indicates a shorted output diode or diodes.
This causes undercharging and also allows the
battery to discharge through the regulator and field
with the engine stopped.
GENERATOR
*
Regulator Sense Voltage
1.
Start the engine.
2. With the engine running at 1000 to 1200 rpm, check
the voltage from the “0” terminal to ground.
GENERATOR
VOLTMETER
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