Internal structure of rotary switch and matters needing attention in installation and use

　　Rotary switchIt is also essentially a knife switch. However, the operating handle of the conventional knife switch is rotated upward or downward on a plane perpendicular to the mounting surface, and the operating handle of the rotary switch is rotated leftward and rightward on a plane parallel to the mounting surface. It can be used to connect or disconnect circuits, replace power supplies or loads, measure three-phase voltages, and control the forward reversal of small motors.

There are many series of rotary switch, here only introduce the national unified design products HZ10 series rotary switch. The rotary switch has the advantages of long-lasting life, reliability and structural simplicity, and is very suitable for the introduction of power supplies below AC 50Hz, 380V, and DC 220V. In the direct start of the small-capacity motor below the 5 kW, the forward and reverse control of the motor and the lighting control circuit of the machine, it shall not exceed 15 to 20 times per hour.

Type HZ10-10/3 toggle switch shape. It is composed of multiple contacts, so it is also called a combination switch.

The HZ10 series transfer switch is selected according to the type of power supply, voltage level, the number of contacts required and the motor capacity. The rated current of the rotary switch is generally 1.5 to 2.5 times the rated current of the motor.

In practice, there are many cases in which a proximity switch such as a conveyor belt or an elevator is used to detect rotating equipment. Here we take the elevator as an example.

A detection device is installed on the tail wheel of the elevator. When the nose wheel slips or the elevator is not dead, the detection device will send a protection signal to make the elevator cut off the power of the motor, thereby protecting the equipment.

　　Rotary switchCircuit analysis:

After pressing the start button, the circuit starts to work and the motor starts to work. If the motor is unable to rotate due to overload, one condition of the detected hardware is that the tooth is just away from the proximity switch. At this time, the proximity switch is closed, the relay KA1 is engaged, the NNO KA1 is opened, and the time relay KT1 supplies power.

When the setting time is 10S, because the detected hardware does not return, the time relay NNO KT1 is closed after 10S, the relay KA is opened, the NC KA is disconnected, the motor control circuit is powered off, and the equipment is protected. Another situation is where the teeth are not close to the proximity switch. At this time, the relay KA1 has no electricity, the time relay KT2 receives electricity, and after 10S, the relay KA receives electricity, the motor control circuit is powered off, and the equipment is also protected.

Extension:

The above approachRotary switchThe working principle is the traditional relay contact working principle, which has defects in processing speed and accuracy.

The above circuit diagram is converted into PLC ladder diagram and controlled by PLC, which greatly improves the processing speed and reliability.