Patent ID: 6992465

Claim:
A generator control circuit of an ac generator for charging a battery which includes a field coil, said generator control circuit comprising: a voltage regulator for regulating an output voltage of said ac generator to a regulation voltage, a comparator for providing a first signal when the output voltage of the ac generator is equal to or lower than the regulation voltage and higher than a predetermined voltage which is higher than voltage of said battery when said battery is open; means for alarming when said comparator does not provide the first signal; and a discrimination circuit connected to the field coil, wherein: said voltage regulator comprises a first switch having an output terminal connected to the field coil; the predetermined voltage of said comparator is equal to the regulation voltage so that said comparator provides a regulation voltage signal to turn on or off said first switch to control current supplied to the field coil when the output voltage becomes higher than the regulation voltage; the first signal is formed from the regulation voltage; and said discrimination circuit provides a signal for resetting said holding circuit to hold said alarming means operative if field current is not controlled by said first switch irrespective of the first signal.