Front view of completed altenator ready to install in coach

Notice the "Turbo" cover on the Fan. It helps to move more air through the Alternator. (Better Centrifical Air Pump) The cooling air is actually sucked through the alternator like a Vacuum Cleaner. It flows from the rear of the alternator to the front.
Even Though there is a double belt pully installed, I still use only one belt. (Proper Belt tension keeps squeels away and 2 belts significantly decreases the power to the power steering pump.)


HOW AN ALTERNATOR WORKS
(Taken From "Alternator and starter parts Wholesale" Website)
1. SWITCH ON
When you switch 'on' the ignition, a red lamp on the dash board lights, providing current through the lamp to the alternator rotor. This current in the rotor establishes a (very small) magnetic field across the rotor.

2. ROTATION
As the engine spins, the rotor's magnetic field passes the stator windings such that the stator windings see a north pole followed by a south pole repetitively. This induces a voltage in the stator windings that similarly changes from positive to negative. [Note that the induction only occurs when the field changes with the rotation of the rotor.

3. RECTIFICATION
This stator voltage is sent through the rectifier that connects the negative voltage from the stator to the battery negative, and the positive voltage from the stator to the battery positive. The rectifier only performs this connection when the alternator voltage exceeds the battery voltage. Once connected the alternator starts to supply current to the battery. The amount of this current is proportional to the current in the rotor. The regulator requires an excess of about 0.7 volts before it will pass significant current. This voltage drop times the current going through the rectifier produces power that is lost through heat. In other words it will get hot, hotter with the more work it does.

4. REGULATION
The voltage regulator limits the alternator output voltage by reducing the rotor current. The dash board lamp can only supply a small current, not enough to realize the full potential of the alternator. Therefore some extra diodes (Diode Trio) in the rectifier circuit, take some of the output power of the stator to supply rotor current via the regulator. This extra diode supply also enables the red dash board lamp to turn off.