| 摘要 |
PURPOSE: To detect the passage of the specified position of a rotor by finding two instants when the magnetic fluxes generated in one piece of coil magnetically coupled change by a maximum value or a specified value. CONSTITUTION: A stator 1 has a circular opening 4 to accommodate a rotor 2 comprising a permanent magnet, and it is equipped with a shunt 5 where a coil 3 is wound. The stator 1 has two sections 1a and 1b of high magnetic resistance at both ends of the diameter of the opening 4, and the rotor 2 is provided with two pieces of notches 6 and 7 to generate positioning torque C on the diameter. The instant t1 when the rotor 2 rotates and the magnetic flux generated in the coil 3 comes to a maximum value Fm is obtained. Next, the magnetic flux Fo generated when the rotor 2 rotates and comes to the specified position and the instant t2 are obtained. The time when it generates the magnetic flux change Fm-Fo is obtained from t2 -t1 . Hereby, the specified position passage of the rotor is detected without fail. |
