PHASE CONTROLLER OF CLEANING DEVICE

摘要

PURPOSE:To commonly use 50/60Hz by switching a charging circuit for deciding a trigger timing in response to a commercial power source frequency. CONSTITUTION:A motor driven blower 101 and a bidirectional thyristor 102 are connected in series with an AC power source. A zero cross detector 103 generates a pulse when the voltage waveform of the power source crosses zero volt, and a counter 106 counts pulses during a period set by a free-running multivibrator 107. A frequency detector 108 discriminates the magnitude of the counter 106 to detect 50/60Hz, turns ON a bidirectional thyristor 109 or 111 to select a variable resistor 110 or 112. The capacitor 113 is charged through the resistor 110 or 112, and when it arrives at the breakover voltage of a trigger element 114, the thyristor 102 is turned ON.