Aspects of temperature rise measurement and temperature protection of rotating electrical machines, with particular reference to increased safety motors and operation at variable speed

Guaranteeing that the temperature of apparatus installed in a hazardous area does not rise to a level which would cause ignition of the hazardous gas/air mixture is a vital part of all the protection concepts. The author reviews some aspects of temperature measurement and control relating to rotating electrical machines. The aspects are looked at particularly from the point of view of satisfying the certifying authority that they are justified in issuing a certificate confirming compliance with one of the relevant standards