Alternator Precautions - Ford Ranger Maintaince And Repair Manual

Exploded view of the alternator. Note the fan is externally mounted, however, internal mount fans are also used
The battery is connected to the alternator at all times, whether the ignition key is turned ONor not. If the
battery were shorted to ground, the alternator would also be shorted. This would damage the alternator. To
prevent this, a fuse link is installed in the wiring between the battery and the alternator. If the battery is
shorted the fuse link melts, protecting the alternator.

Alternator Precautions

To prevent damage to the alternator and regulator, the following precautions should be taken when working
with the electrical system.
• Never reverse the battery connections.
Booster batteries for starting must be connected properly: positive−to−positive and
•
negative−to−ground.
Disconnect the battery cables before using a fast charger; the charger has a tendency to force current
•
through the diodes in the opposite direction for which they were designed. This burns out the diodes.
Never use a fast charger as a booster for starting the vehicle.
•
• Never disconnect the voltage regulator while the engine is running.
• Avoid long soldering times when replacing diodes or transistors. Prolonged heat is damaging to AC
generators.
• Do not use test lamps of more than 12 volts (V) for checking diode continuity.
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