Importance

Loading Importance Indicators...

Abstract

A controller of a DC brushless motor comprises a microcomputer. The microcomputer receives signals from three hall elements being disposed in association with the DC brushless motor and for detecting the rotating position of a rotor magnet of the DC brushless motor. On the basis of the position detecting signals, the data of the rotating number of the rotor magnet may be evaluated. When the number of the rotation thus evaluated is below the predetermined rotating number, the microcomputer stops the power supply to the DC brushless motor from a switching power source. In order to evaluate such data of rotating number, an internal interruption is started at every predetermined period in the microcomputer. The microcomputer determines at every internal interruption whether or not a counter which is reset at each rotation of the rotor magnet has overflowed, and the data of rotating number is evaluated on the basis of repetition times of the internal interruptions and periods required for such overflow.

Loading the Abstract Image...

First Claim