Forensic engineering and drive lifetime

CIM Bulletin, Vol. 93, No. 1044, 2000

A.C. Stevenson, Robicon Canada, Peterborough, Ontario

The most common theory is that, since thyristors, diodes, and insulated gate bipolar transistors (IGBTs) are Òsolid stateÓ they will live forever. This is not so. They have wear-out mechanisms (e.g. insulation) and other mechanical parts such as motor bearings. These wear-out phenomena can be easily calculated. In this paper we will look at some of the failures and the failure rate of thyristors in power converters to see what affects them and to see what improvements can be made. If converter failures do occur, some simple forensic engineering steps will show if this is the root cause of the problem.
Mots Clés: Forensic engineering, Thyristors, Diodes, Thermal fatigue, Semi-conductor.