Control apparatus for a vehicular alternator

A control apparatus for a vehicular alternator in which said vehicular alternator includes:

• an armature coil wound around a stator core;
• a rectifier circuit connected to said armature coil;
• a rotor arranged in a manner to be rotatable relative to said armature coil;
• a rotor coil for exciting a magnetic pole of said rotor to an N polarity and an S polarity;
• and
• a voltage control circuit that controls a power generation voltage output from said rectifier circuit so as to be substantially constant;
• wherein said rectifier circuit has an AC input terminal for taking in an alternating voltage generated in said armature coil for rectification thereof into a direct current, a positive output terminal for outputting a direct current positive voltage, and a negative output terminal for outputting a direct current negative voltage;
• said voltage control circuit controls said power generation voltage so as to be substantially constant by interrupting a field current of said rotor coil when said power generation voltage exceeds a first predetermined voltage, while passing said field current when said power generation voltage is equal to or lower than said first predetermined voltage;
• said voltage control circuit comprises:
• a circulation circuit composed of a series circuit comprising a diode and a current attenuation element that circulates said field current upon interruption thereof;
• a short-circuiting circuit that short-circuits said current attenuation element;
• and
• a short-circuit control circuit that opens said short-circuiting circuit when said power generation voltage exceeds a second predetermined voltage.