What is the structure and function of low-voltage electrical appliances?
Low-voltage electrical appliances generally have two basic parts: one is the sensing part, which senses the external signal and makes a regular reaction. In the self-controlled electrical appliance, the sensing part is mostly composed of an electromagnetic mechanism, in the controlled electrical appliance, the sense The measuring part is usually an operating handle or the like; the other is an executing part, such as a contact that is turned on or off according to an instruction.
The role of low-voltage electrical appliances
The low-voltage electrical appliance can automatically or manually change the state and parameters of the circuit according to the requirements of the operation signal or the external field signal to realize the control, protection, measurement, indication and adjustment of the circuit or the controlled object. The role of low-voltage electrical appliances is:
(1) Control role. Such as the elevator's up and down movement, fast and slow automatic switching and automatic stop layer.
(2) Protection. According to the characteristics of the equipment, the equipment, the environment, and the human body can be automatically protected, such as overheat protection of the motor, short circuit protection of the power grid, and leakage protection.
(3) Regulation. Low-voltage electrical appliances can adjust some of the power and non-electricity to meet the requirements of users, such as the adjustment of the throttle of the diesel engine, the adjustment of the temperature and humidity of the room, and the automatic adjustment of the illumination.
(4) Measurement effect.
Use instruments and their appropriate electrical appliances to measure equipment, power grid or other non-electrical parameters such as current, voltage, power, speed, temperature, humidity, etc.
(5) Indication. Using the functions of control and protection of low-voltage electrical appliances, the operating conditions of the equipment and the working conditions of the electrical circuits, such as insulation monitoring and protection of card-off instructions, are detected.
(6) Conversion effect. Switch between the electrical equipment or put the low-voltage electrical appliances and control circuits into operation in time to realize the function switching, such as manual and automatic conversion of the excitation device, switching of the power supply and the self-supplied power.
Of course, the role of low-voltage electrical appliances is far more than this. With the development of science and technology, new functions and new equipment will continue to emerge. The main types and uses of commonly used low-voltage electrical appliances are shown in the table.
The requirements for low-voltage distribution electrical equipment are strong arc-extinguishing ability, good breaking capacity, good thermal stability and accurate current limiting. For low-voltage control appliances, it requires reliable operation, high operating frequency, long life and a certain load capacity.