The alternator charging system is a negative (-) ground system which consists of an alternator, a regulator, a charge indicator, a storage battery and wiring connecting the components.
The alternator is belt-driven from the engine. Energy is supplied from the alternator/regulator system to the rotating field through two brushes to two slip-rings. The slip-rings are mounted on the rotor shaft and are connected to the field coil. This energy supplied to the rotating field from the battery is called excitation current and is used to initially energize the field to begin the generation of electricity. Once the alternator starts to generate electricity, the excitation current comes from its own output rather than the battery.
The alternator produces power in the form of alternating current. The alternating current is rectified by 6 diodes into direct current. The direct current is used to charge the battery and power the rest of the electrical system.
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-negative.
- 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.
- Do not short across or ground any of the terminals on the AC generator.
- The polarity of the battery, generator, and regulator must be matched and considered before making any electrical connections within the system.
- Never operate the alternator on an open circuit. Make sure that all connections within the circuit are clean and tight.
- Disconnect the battery terminals when performing any service on the electrical system. This will eliminate the possibility of accidental reversal of polarity.
- Disconnect the battery ground cable if arc welding is to be done on any part of the car.
REMOVAL & INSTALLATION
While internal alternator repairs are possible, they require specialized tools and training. Therefore, it is advisable to replace a defective alternator, or have it repaired by a qualified shop.
- Open the hood and disconnect the battery ground cable.
- Remove the adjusting arm bolt.
- Remove the alternator through-bolt. Remove the drive belt from the alternator pulley and lower the alternator.
- Label all of the leads to the alternator so that you can install them correctly and disconnect the leads from the alternator.
- Remove the alternator from the vehicle.
- To install, reverse the above procedure.
The fan belt drives the alternator and water pump. If the belt is too loose, it will slip and the alternator will not be able to produce its rated current. Also, the water pump will not operate efficiently and the engine could overheat.
Check the tension of the belt by pushing your thumb down on the longest span of the belt, midway between the pulleys. Belt deflection should be approximately 1 / 2 in.
To adjust belt tension, proceed as follows:
- Loosen the alternator mounting bolt and the adjusting arm bolts.
- Apply pressure on the alternator front housing only, moving the alternator away from the engine to tighten the belt. Do not apply pressure to the rear of the cast aluminum housing of an alternator; damage to the housing could result.
- Tighten the alternator mounting bolt and the adjusting arm bolts when the correct tension is reached.