| 摘要 |
PURPOSE:To remove defective low frequency sound to an induction load by connecting in series a choke filter between the output side of a phase control circuit and the load, and cutting off the spurious component from the phase control circuit. CONSTITUTION:An induction load controller 7 is connected through an induction motor 4' as an induction load connected to an AC power source 8 and a choking coil 9 as a filter at a phase control circuit 5. A resistor 10, a condenser 11 and a resistor 12 connected in series with each other are connected in parallel with a choking coil 9 connected to the input side of the motor 4'. This circuit 5 forms a parallel circuit with a condenser 13, a resistor 14, a variable resistor 15 and a triac 16 of an SCR, and the gate 16' of the triac 15 is connected through a diac 17 between the condenser 13 and the resistor 14. |
