AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING
AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING
AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING
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To calculate charging system output, add the two ammeter readings. This will give you<br />
total charging system output in amps. Compare this figure to the specifications within<br />
the manufacturer's manual.<br />
Current output specifications will depend on the size (rating) of the alternator. A<br />
vehicle with few electrical accessories may have an alternator rated at 35 amps,<br />
whereas a larger vehicle with more electrical requirements could have an alternator<br />
rated from 40 to 80 amps. Always check the manufacturer's service manual for exact<br />
values.<br />
If the charging system output current tested low, perform a regulator voltage test and a<br />
regulator bypass test to determine whether the alternator, regulator, or circuit wiring is<br />
at fault.<br />
Regulator Voltage Test<br />
A regulator voltage test checks the calibration of the voltage regulator and detects a<br />
low or high setting. Most voltage regulators are designed to operate between 13.5 to<br />
14.5 volt range. This range is stated for normal temperatures with the battery fully'<br />
charged. Regulator voltage test procedure is as follows:<br />
Set the load tester selector to the correct position using the manufacturer's manual.<br />
With the load control OFF, run the engine at 2,000 rpm or specified test speed. Note<br />
the voltmeter reading and compare it to the manufacturer's specifications.<br />
If the voltmeter reading is steady and within manufacturer's specifications, then the<br />
regulator setting is okay. However, if the volt reading is steady but too high or too low,<br />
then the regulator needs adjustment or replacement. If the reading were not steady, this<br />
would indicate a bad wiring connection, an alternator problem, or a defective<br />
regulator, and further testing is required.<br />
Regulator Bypass Test<br />
A regulator bypass test is an easy and quick way of determining if the alternator,<br />
regulator, or circuit is faulty. Procedures for the regulator bypass test is similar to the<br />
charging system output test, except that the regulator be taken out of the circuit. Direct<br />
battery voltage (unregulated voltage) is used to excite the rotor field. This should allow<br />
the alternator to produce maximum voltage output.<br />
Depending upon the system there are several ways to bypass the voltage regulator. The<br />
most common ways are as follows:<br />
Sorting a test tab to ground on the rear of the alternator (if equipped).<br />
Placing a jumper wire across the battery and field terminals of the alternator.<br />
With a remote regulator, unplug the wire from the regulator and place a jumper wire<br />
across the battery and field terminals in the wires to the alternator.<br />
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