Voltage regulator for vehicles

A battery charging system for vehicles comprising:

• an A.C. generator;
• a rectifier for rectifying the output of said A.C. generator;
• a battery charged from the output of said rectifier;
• and
• a voltage regulator for regulating the output of said A.C. generator;
• said regulator including,
• means for controlling the excitation of a field winding of said generator, said controlling means controlling a current flow to the field winding by detecting a voltage level of said battery, the current being supplied to said field winding from said battery and through an ignition switch at an initial excitation stage and the current being supplied from said generator through said rectifier at a full excitation stage succeeding to the initial excitation stage,
• means for detecting an output voltage level of said generator, said detecting means having a single input terminal connected to an output terminal of a stator winding of said generator and producing first and second detection signals when said generator output voltage respectively reaches first and second predetermined reference levels,
• means for providing an on-off control signal of a predetermined duty ratio to said excitation control means, said on-off control signal providing means having an input terminal to receive said first detection signal from said detecting means to continuously deliver said on-off control signal to said excitation control means until said first detection signal is received, thereby to supply the current to said field-winding intermittently at said predetermined duty ratio, and
• means for indicating a generating state of said generator in response to said second detection signal from said detecting means, said indicating means indicating that said generator is not in a normal generating state until said second detection signal is received.