| 摘要 |
PROBLEM TO BE SOLVED: To measure the rotational period with high accuracy irrespective of high/low rotational speed, by increasing the frequency of the reference clock during the high rotation, and decreasing the frequency during the low rotation in a period for each rotation of a rotor in the synchronous rotation with that of an induction motor. SOLUTION: A pulse signal detected by a detecting means 6 is divided by a first motor divider 7, and transmitted to a measuring means 10. The reference clock of a CLK 8 is divided according to the division ratio signal of an inverter device 1, and the reference clock divided by the inverter 1 is transmitted to first and second counters 10a, 10b. The section of the pulse 13 of the pulse signal by the detecting means 6 is counted by the reference clock to measure the count number in the motor rotational period, and the count number of the reference clock in the motor rotational period is converted into the motor rotation frequency. The speed of an induction motor 3 can be controlled by comparing the motor rotational frequency with the set value by the inverter device 1 to control the output frequency. |
