| 摘要 |
PURPOSE:To secure the minimum turn ON time and to ensure compliance with an emergency stopping instruction, by providing a forbidding circuit which forbids the output during the minimum ON time before and after a synchronizing signal at the input and output sides of the distributor of a control circuit. CONSTITUTION:A frequency command signal is converted in a V-F converter 2, and the result is outputted to the distributor 3 and a traiangular wave generator 4. An output signal B and a voltage command (a) and an output signal B and a voltage command (b) are compared in comparators 5 and 6, respectively. Voltage pulse width signals C and D are obtained, introduced into a logic circuit 10, and distributed by output signals RCu, RCv, and RCw of the distributor 3. The results are made to be control signals Lu, Lv, and Lw for the inverter and inputted to an AND circuit AND in the forbidding circuit 14. A signal, which forbids the generation of the minumum ON time signal that is generated in the vicinity before and after the input synchronizing signal A to said distributor 3, is generated. The signal is made to be a start stop condition signal. |
