This part of IEC 60947 specifies rules for control units, which perform the switching functions in response to the thermal detectors incorporated in rotating electrical machines according to IEC 60034-11, and the industrial application.It specifies rules for that type of system comprising a positive temperature coefficient (PTC) thermistor detector having particular characteristics, and its associated control unit.This consolidated version consists of the first edition (2003) and its amendment 1 (2006). Therefore, no need to order amendment inaddition to this publication.