Method and device for detecting failure of excitation circuit of polyphase alternator

A method for detecting the failure of an excitation circuit of a polyphase alternator controlled by a regulator said method comprising the following steps:

• e) continuously taking electrical information (Iexc;
• Von) other than a phase signal from said excitation circuit;
• f) continuously comparing said electrical information taken in step a) with a predetermined threshold value (Iref, Vref);
• g) continuously determining a logic state (LT) according to the result of the comparison made in step b);
• and
• h) signalling an electrical continuity fault of said excitation circuit if said logic state (LT) determined in step c) persists for a time at least equal to a predetermined delay time (6);
• said electrical information taken being a breakdown voltage (Von) of a switching transistor (2) of said excitation circuit and said threshold value being a predetermined reference voltage (Vref).