| 摘要 |
1,085,520. Control of A.C. motors. SIEMENSSCHUCKERTWERKE A.G. Aug. 30, 1966 [Aug. 28, 1965], No. 38718/66. Heading H2J. One or more asynchronous motors 2 are supplied from an A.C. source via a controllable rectifier 9 and self-commutating inverter 4, the frequency of which is controlled by 5 so that, if the A.C. supply voltage drops for a predetermined time (about 1 sec.) by at least a predetermined amount the frequency is reduced so that the motor regenerates to charge a capacitor 7 to a voltage corresponding to the instantaneous frequency. The object is to ensure continuity of commutation of the inverter. In addition the frequency, and also the voltage output of rectifiers 9, is controlled so as to maintain constant flux in the motor by a device 10, which compares a reference value 18 either with a signal from a Hall probe, or from a circuit 14, 15,16 which provides a voltage corresponding to flux. |
