A survey of fault diagnosis and protection theory of large induction motors

The theories of fault diagnosis and protection of large induction motors are dealt with in this paper, which include: the conventional protection based on the detection of over currents; the microprocessor based protection with the principle of symmetrical components; the on line monitoring and fault diagnosis based on the advanced signal processing techniques and the multi loop theory. It is believed that the breakthrough of the quantitative analysis for internal faults is the key problem to implement the early diagnosis of large motors, and the combination of the theory with the advanced signal processing methods and microprocessor technique will make a great progress in this field.