JPH0317787U - - Google Patents

Description

[Brief explanation of drawings]

Fig. 1 shows the conventional controller, Fig. 2 shows the switch section of the first embodiment, Fig. 3 shows the switch section of the second embodiment, Fig. 4 shows the switch section of the third embodiment, and Fig. 5 shows the switch section of the embodiment 1 to 3. A timing chart for opening and closing the switch, FIG. 6 is an explanatory diagram showing the voltage applied to the motor and current flowing under phase control, and FIG. 7 is an explanatory diagram showing the opening and closing states of the switch.

Claims (1)

[Scope of utility model registration request] In a motor speed control circuit that controls the speed of the motor by controlling the phase of the voltage applied to the motor,
Opening and closing of the circuits on the main circuit side, which includes a load circuit in which the motor is connected as a load to the power supply and phase control element of the speed control circuit, and on the gate circuit side, which provides a trigger signal to the gate of the phase control element of the load circuit. The circuit breaker S ₁ and the circuit breaker S ₂ are provided in conjunction with both circuits, and the circuit breaker S ₁
, _S2 , the switch operating member of the circuit breaker _S1 of the main circuit is attached with an operating load device for delaying the interruption, and the switch operating member of the circuit breaker S1 of the main circuit is attached to the switch operating member of the main circuit circuit breaker _S1 for advance closing. A speed control device for a sewing machine, characterized by having a protruding arm for operation.