PURPOSE: To obtain the vacuum cleaner which does not generate a motor input loss at the time of selecting the maximum input and is free from a motor input difference caused by a difference of a commercial frequency by providing a maximum input selecting switch for always supplying a gate current to a thyristor by short-circuiting a trigger circuit.
CONSTITUTION: On the photodetecting side of a photocoupler 20 in a trigger circuit 12, that is, on the gate side of a triode AC switch 4, a strong notch switch 23 which is subjected to turn-on operation at the time of selecting the maximum input is provided in parallel. This switch 23 is attached, for instance, to the upper face of a cleaner main body 24 in which a motor-driven air blower 3 is contained, and it is operated at the time of selecting the maximum input, that is, at the time of switching to a strong notch. When the switch 23 is subjected to turn-on operation, the triode AC switch gate side of the trigger circuit 12 is short-circuited, a gate current is always supplied to the triode AC switch 4 irrespective of turn-on and turn-off of the trigger circuit 12, and the triode AC switch 4 continues the turn-on state. As a result, no motor input loss is generated in the motor-driven air blower 3.
OTANI TOSHIO
SAKATA SOJI
UENO HITOHISA
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