Abstract: To provide a vehicular charging and generating system capable of issuing alarm to a driver even when failure is caused in a rectifying apparatus of the vehicular charging and generating system, failure detecting means issues alarm when a difference between an output voltage of generated voltage detecting means and an output voltage of average phase voltage detecting means is higher than first difference voltage set when failure is not caused in a rectifying element or when the difference is lower than second difference voltage set when failure is not caused in the rectifying element.

Abstract: To provide a vehicular charging and generating system capable of issuing alarm to a driver even when failure is caused in a rectifying apparatus of the vehicular charging and generating system, failure detecting means issues alarm when a difference between an output voltage of generated voltage detecting means and an output voltage of average phase voltage detecting means is higher than first difference voltage set when failure is not caused in a rectifying element or when the difference is lower than second difference voltage set when failure is not caused in the rectifying element.

Abstract: A control device for a motor vehicle electric generator takes into account the relationship between field currents flowing through field windings of charging generators having different generation powers and output currents. The field current is increased once and instantly at the time of loading but prior to suppressing the increasing speed of the field current. The amount of the increase of the field current is controlled to be proportional to the field current before the loading. The control device according to the invention can be used for charging generators having different power generation capacities, and the battery voltage drops at the moment when switching in a motor vehicle electric load are reduced to substantially the same level.

Abstract: A control device for a battery charging AC generator for a motor vehicle including a power transistor connected in series with a field winding of the AC generator for performing switching control of a current flowing through the field winding. A voltage deviation circuit detects a deviation of the battery voltage from a reference voltage; and a PWM signal generating circuit is responsive to a voltage deviation signal from the voltage deviation circuit for turning the power transister on and off a resistor connected in series with the power transistor detects a current flowing through the field winding; and a current limiting circuit generates a turn off signal for the power transistor when the detected current is determined to have exceeded a reference current. A latch circuit operates in response to a clock signal from the PWM signal generating circuit to limit the frequency of turning on and off of the power transistor to below 1 KHz.