METHOD FOR DETECTING A DEFECTIVE COOLING FAN AND FOR GENERATING AN ALARM SIGNAL

摘要

The method involves computing an alarm switch-on revolution rate from a current revolution rate demand value at regular intervals using a defined relationship, checking at intervals whether the current revolution rate is in a range outside that defined by the desired and alarm switch-on rates and on the side of the range remote from the desired rate; if so an alarm switch-on criterion is generated. AN Independent claim is also included for the following: a motor with an arrangement for monitoring the deviation of the actual revolution rate from a normal zone.