Patent ID: 7791352

Claim:
A method for detecting faults in semiconductor components in electrical machines corresponding to three-phase generators and having multiple windings and multiple phase terminals, comprising the method steps: a) putting one of the phase terminals under a load to ground, or to a higher potential, and measuring a resulting phase terminal potential, to detect short circuits to a positive pole of a battery (B+) or to ground when the electrical machine is at rest; b) measuring one of a plurality of voltages in one of the phase terminals to detect the presence of ground potential or a potential of the positive pole (B+) of the battery at the one of the phase terminals, to detect short circuits to the positive pole (B+) of the battery or to ground during operation of the electric machine; c) measuring one of the plurality of voltages in one of the phase terminals to ascertain whether the one of the plurality of voltages falls below a defined minimum value or exceeds a defined maximum value, to detect interruptions during operation of the electrical machine; d) detecting, in a single measured phase terminal, particular voltage values at defined times corresponding to a point on the leading edge and a point on the trailing edge of the measured voltage, and comparing the two detected voltage values to produce a difference value, which is compared to a limiting value, and if the difference value is greater than the limiting value, determining the existence of a fault condition; and e) storing the detected faults in a fault memory of a control unit which is read out via a diagnostic plug.