DEVICE FOR DETECTING MOTOR REVOLUTION

PROBLEM TO BE SOLVED: To provide a motor revolution detection device that restrains the number of revolutions far from the real number of revolutions of a motor from being detected. SOLUTION: In the motor revolution detection device, a memory 42 stores the cycle of pulse signals measured with a measurement unit 43 in order as cyclic data. An operation unit 41 calculates the moving average of a specified number of pieces from the newer one out of stored cyclic data each time the memory 42 stores the cyclic data, and calculates the number of revolutions of the first fan motor 101 and the second fan motor 102 from the moving average. Thereby, even when noise is received as a pulse signal and that an abnormal value is stored as cyclic data, the abnormal value is smoothed by the moving average of the cyclic data for a specified number pieces, so it is restrained that the number of revolutions far from the real number of revolutions is computed. COPYRIGHT: (C)2011,JPO&INPIT