| 摘要 |
PURPOSE:To construct the circuit at low cost, while to prevent the generation of conversion loss at the speed control circuit for the AC motor by a method wherein an AC power source of integer times of the commercial power source is obtained directly from the commercial power source using full-wave rectification circuits of four pieces. CONSTITUTION:The first and the second full-wave rectification circuits connected in series, and the third and the fourth full-wave rectification circuits connected in seies are connected in parallel with the secondary side of an insulating transformer T1 to output the balanced secondary voltage. Moreover the AC motor M is loaded between the series node of the first and the second full-wave rectification circuits and the series node of the third and the fourth full-wave rectification circuits. The transistors Tr1-Tr4 of photo couplers are controlled according to the outputs of a logic part alpha, and currnt paths between the positive and the negative terminals of the full-wave rectification circuits are closed by the unit of 1/4 period of the commercial power source voltage. |
