| 摘要 |
PURPOSE:To drive a motor of a different size by using the same transformer by providing a coil in parallel with a secondary side coil at the output side of a transformer of a driving circuit, and providing a switch for connecting and disconnecting the secondary side to or from the coil in response to the size of the motor. CONSTITUTION:A microcomputer 12 determines driving frequencies of ultrasonic motors 1, 22 in response to the output value of an A/D converter 11, and sends data to a D/A converter 13. A voltage control oscillator 14 oscillates a pulse of a frequency responsive to the output value of the converter 13. The oscillated pulses are divided by four by a ring counter 15, and sequentially sent to transistors 16, 17, 18, 19. The transistors 16, 17, 18, 19 are repeatedly turned ON, OFF to convert a current from a power source 30 to an AC voltage to be applied to the primary sides of transformers 20, 21. Secondary side AC voltages are supplied to electrode groups 3, 24 through the contacts of a relay 7, to electrode groups 4, 25 through the contacts of a relay 8 to drive the motors 1, 22. |
