| 摘要 |
<p>A speed control unit for two-phase or three-phase induction motor can be used in ventilation equipment. It provides two out-of-phase variable frequency voltages and does not need the use of a compensating capacitor at the motor. The unit operates from a voltage (V1) which can be varied. It has a sub-unit (2) which transforms the input voltage (V1) into another voltage (V2). The second voltage (V2) varies linearly with time. Another sub-unit (3) generates two voltages (Va1, Va2) can be set by the amplitude of the first voltage. Two power amplifiers (4, 5) are used to give two control voltages (V4 V5) for the motor.</p> |
