AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING
AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING
AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING
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Figure 2-28.- Typical diode.<br />
Since the engine speed varies in a vehicle, the frequency also varies with the change of<br />
speed. Likewise, increasing the number of pairs of magnetic north and south poles will<br />
increase the frequency by the number pair of poles. A four-pole generator can generate<br />
twice the frequency per revolution of a two-pole rotor.<br />
ALTERNATOR OUTPUT CONTROL<br />
A voltage regulator controls alternator output by changing the amount of current flow<br />
through the rotor windings. Any change in rotor winding current changes the strength<br />
of the magnetic field acting on the stator windings. In this way, the voltage regulator<br />
can maintain a preset charging voltage. The three basic types of voltage regulators are<br />
as follows:<br />
Contact point voltage regulator, mounted away from the alternator in the engine<br />
compartment<br />
Electronic voltage regulator, mounted away from the alternator in the engine<br />
compartment<br />
Electronic voltage regulator, mounted on the back or inside the alternator<br />
The contact point voltage regulator uses a coil, set of points, and resistors that limits<br />
system voltage. The electronic or solid-state regulators have replaced this older type.<br />
For operation, refer to the "Regulation of Generator Output" section of this chapter.<br />
<strong>AUTOMOTIVE</strong> <strong>ELECTRICAL</strong> <strong>CIRCUITS</strong> <strong>AND</strong> <strong>WIRING</strong> 34/ 101