To conduct a normal operation with no chattering by providing a hole IC detecting the actual revolving speed of a motor, and assembling an electronic power device cutting off an auxiliary winding circuit when the actual revolving speed of the motor reaches the predetermined cutoff revolving speed into the electric circuit of the motor.
The electric circuit of a motor is provided with a hole IC4 detecting the actual revolving speed of the motor. A control device 5 setting the cutoff revolving speed and recovery revolving speed of an auxiliary winding circuit and an electronic power device 6 cutting off the auxiliary winding circuit when the motor reaches the prescribed revolving speed are assembled into the electric circuit of the motor. A split-phase start motor starts rotating by the excitation to a main winding 2 and an auxiliary winding 3 for an operation, and the electronic power device 6 cuts off the excitation to the auxiliary winding 3 when the IC 4 detects that the actual revolving speed of the motor reaches the numerical value set by the control device 5. The cutoff timing is slightly delayed by the control device 5, thus acceleration torque is generated, and a normal operation can be conducted.
SUZUKI TAKESHI
YABU MASANORI
FUKUSHIMA SHOZO
