| 摘要 |
PURPOSE:To detect a rotational frequency with high precision by connecting the secondary winding of the 1st rotating machine of a rotor which rotates by being coupled with a stator and a rotating body to the primary winding of the 2nd rotating machine. CONSTITUTION:Rotary sensors 1A and 1B consist of the 1st and the 2nd rotating machines 4a and 4b which have the same constitution that a winding type induction motor has. The secondary winding L2 of the rotating machine 4a and the primary winding L1 of the rotating machine 4b are connected mutually, so a voltage of reference frequency from a reference voltage source 8 is applied to the winding L1 of the rotating machine 4a through a terminal t1 to establish a rotating magnetic field, thereby inducing a voltage of slip frequency accurately proportional to the rotating speed of the rotating body 7, i.e. rotor 3 across the winding L2 of the rotating machine 4b. Then, an arithmetic processor 9 calculates the frequency of the induced voltage from the reciprocal of the digital counted value of clock pulses to calculate the rotational frequency from the difference between the frequency and reference frequency.
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