| 摘要 |
PURPOSE:To obtain power with a constant speed and a constant direction regardless of variation in line frequency, by changing over the direction of rotation according to the variation in the line frequency and changing the speed reduction ratio according to the rotational direction. CONSTITUTION:When the line frequency of an electric powr source 1 is 50Hz, a frequency discriminating circuit 6 energizes a relay 4 which operates by positive rotation and closes ite contact point 4a. Then, a motor 2 turns positively at a number of rotation, n1, and the output shaft of a reduction gear 7 rotates, for instance, clockwise at N1=n1/50 based on the reduction ratio 50. If the line frequency is 60Hz, the relay 5 which operates by negative rotation is energized, and the motor 2 rotates in th opposite direction at the number of rotation, n2 (n2=1.2Xn1). Then the output shaft of the reduction gear 7 rotates by the number of rotation, n2=n2/ 600=1.2Xn/60=n1/50=N1 based on the reduction ratio, 60, in other words, by the same number of rotation as when the line frequency is 50Hz. Accordingly, the motor gets rotational power in constant direction and at constant speed in spite of change in line frequency. |
