A low-voltage circuit breaker, formerly known as an automatic switch, is an electrical switch that can not only connect and disconnect normal and over-load currents but also interrupt short-circuit currents. In addition to its control function within a circuit, the low-voltage circuit breaker also offers certain protective features, such as over-load, short-circuit, under-voltage, and leakage protection. There are many ways to classify low-voltage circuit breakers; by usage type, they are categorized into selective (adjustable protection parameters) and non-selective (non-adjustable protection parameters), and by arc-quenching medium, they are air-operated and vacuum-operated (domestic models are mostly air-operated). The capacity range of low-voltage circuit breakers is extensive, ranging from as low as 4A to as high as 5000A. They are widely used in the distribution systems of various levels, for power control and protection of electrical terminals in machinery and equipment.
What are the functions of low-voltage circuit breakers?
Low-voltage circuit breakers are used in low-voltage circuits to prevent short circuits in electrical equipment. They also help avoid hazardous accidents in the event of abnormal voltage or current.
Low-voltage circuit breakers are suitable for machine tools, as they do not require frequent startups, thus avoiding injuries.
Alarm contacts are included in the low-voltage circuit breakers. In the event of excessive circuit load or a short circuit, the alarm contacts will emit a sound or an indicator light to alert individuals and prevent major accidents.
What is the wiring method for circuit breakers?
Breakers are available in front-panel, rear-panel, plug-in, and drawer-style wiring configurations. Unless otherwise specified by the customer, all are supplied with front-panel wiring, which is a common wiring method.
(1) Rear Wiring Method: A significant feature of the rear wiring is that it allows for the replacement or maintenance of circuit breakers without the need for re-wiring; simply disconnect the primary power source. Due to the unique structure, the product is pre-configured with mounting plates, screws, and wiring screws according to design specifications. It is crucial to pay special attention to the reliability of the contacts for the high-capacity circuit breakers, as it directly affects the normal operation of the circuit breakers. Therefore, installation must be taken seriously and strictly followed the manufacturer's instructions.
Plug-in wiring: First, install a circuit breaker mounting bracket on the installation board of the complete set. The mounting bracket has 6 connectors, and the circuit breaker's connection plate has 6 sockets. There are bolts on the surface of the mounting bracket or at the back of the mounting bracket. The mounting bracket is pre-wired with power and load lines. During use, simply plug the circuit breaker directly into the mounting bracket. If the circuit breaker fails, just remove the faulty one and replace it with a new one. The replacement time is shorter and more convenient compared to wiring before or after the board. Due to the need for manual insertion and removal, the shell current rating of our plug-in products is limited to a maximum of 400A, thus saving maintenance and replacement time. When installing, check if the circuit breaker's plug is securely fastened, and securely fasten the circuit breaker to reduce contact resistance and improve reliability.
(3) Drawer-style wiring: The incoming and outgoing drawers of the circuit breaker are rotated clockwise or counterclockwise by a lever. Both the main and secondary circuits use an insertable structure, omitting the isolator required for fixed installations, thus achieving dual functionality with one unit, enhancing cost-effectiveness. This also greatly facilitates operation and maintenance while increasing safety and reliability. Particularly, the main circuit knife blade socket of the drawer base is compatible with NT-type fuse circuit breaker knife blade sockets, allowing for direct insertion of fuses for emergency power supply.
