| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive and small coil switching device for a three- phase AC motor by reducing semiconductor switching elements as much as possible by shortening the time required for switching the coils. SOLUTION: The coil switching device for the three-phase AC motor comprises the AC motor having a plurality of coils in respective phases, a coupling terminal for coupling the plurality of the coils and both terminals of the respective phase coils provided out of the motor, a coil switching means for suitably switching the coupling terminal, and a variable frequency power source for supplying a variable-frequency and variable-voltage to the AC motor. The coil switching means has a plurality of three-phase rectifying means connected at one end of the phase coil to the variable-frequency power source, connected at the other end to the coupling terminal, to the AC side input terminal of the 3-phase rectifier means in the respective phases, and a semiconductor switch provided to open or close both ends of the DC output side of the three- phase rectifier means. |
