Systems and methods for detecting of abnormality in magnetic rotors

A magnetic rotation detector comprising:

• a magnetic rotor having magnetic bodies disposed on an outer periphery portion thereof at intervals of a predetermined distance;
• a detecting body that detects a change in magnetic flux that is caused by the magnetic bodies as the magnetic rotor rotates;
• and
• an abnormality determination portion that monitors an apparent fluctuation in rotational speed of the magnetic rotor based on a result detected by the detecting body and that determines that the magnetic rotor is in an abnormal state if the fluctuation occurs at a specific position of the magnetic rotor,
• wherein
• the abnormality determination portion detects the occurrence of the fluctuation at the specific position of the magnetic rotor by making a determination on a distance between apparent positions of the magnetic bodies which correspond to the apparent fluctuation in rotational speed, and calculates the distance on the basis of a product of an interval of generation of noise in an output signal detected by the detecting body and a rotational speed of the magnetic rotor at the time of generation of noise.