Voltage regulator of a motor vehicle alternator, regulator brush-holder, and corresponding alternators

Voltage regulator (1, 30, 39) of a motor vehicle alternator (2, 44) of the type comprising a regulation module (1, 39) which can control an excitation current (lexc) in an excitation winding (3) of said alternator (2, 44), according to a difference (5) between a set voltage (U0) and a regulation voltage (Ubat) of an on-board network (9) of said vehicle supplied by a battery (10) to which said alternator (2, 44) is connected, said regulation module (1, 39) comprising:

• a first earthing terminal (22) which is designed to be connected to an earth (21) of said on-board network (9);
• a first supply terminal (25) which is designed to be connected to a positive line (24) of said on-board network (9);
• a first excitation terminal (27) which is designed to be connected to said excitation winding (3);
• a measurement terminal (25, 40) which is designed to measure said regulation voltage (Ubat);
• and comprising:
• a voltage divider bridge (13), which is connected firstly to said measurement terminal (25, 40) and secondly to said first earthing terminal (22);
• a subtracter (14) which is connected at its input to said set voltage (U0), and to a midpoint of said voltage divider bridge (13);
• a regulation loop (12) which is connected at its input to said subtracter (14), and controls at its output a first semiconductor switch (16) which is connected between said first supply terminal (25) and said first excitation terminal (27);
• a first free wheel diode (17) which is connected between said first excitation terminal (17) and said first earthing terminal (22);
• wherein it also comprises a safety module (30) which carries out a function of monitoring of said regulation voltage (Ubat), which module is distinct from said regulation module (1, 39).