Electronically controlled and electrically driven devices are replacing mechanically driven components to provide more and more of the functions in an automobile, as well as to extend the range of functions. Demand for stable electrical power has risen and will continue to rise.
As lights and other accessories are turned on and the load on the system increases, the current output to the circuits must be increased and the output voltage must be maintained.
The regulator again adjusts the rotor field circuit, but this time increases the current flow and therefore the magnetic field strength. The induced voltage in the stator rises to maintain system voltage and increase current output. There is no need for a current regulator as the design of the stator winding determines the maximum current output of the alternator at a system operating voltage of 13.8 to 14.2 volts.
If an alternator is rated at 40 amps it is capable of maintaining a system voltage of 13.8 to 14.2 volts up to a current load of 40 amps.
