| 摘要 |
PURPOSE:To suppress a transient phenomenon at the time of OFF switching time thereby to smoothly rotate a motor by connecting an impedance element in parallel with the switching element provided in a circuit to the motor. CONSTITUTION:A switching element 3, such as a triac for controlling an input power to a motor 2 in response to a power source frequency is provided in a circuit 4 from an AC power source 1 to the motor 2. A resistor 5 of an impedance element is connected in parallel with the element 3. When the element 3 is switched, a power source voltage is shared by the motor 2 and the resistor 5, and slightly applied to the motor 2. As a result, since the abrupt variation of the motor current is suppressed, it can prevent the switching timing of the element 3 from becoming unstable. |
