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Circuit Breaker Many Protection Devices
Aug 10, 2017

The circuit breaker is a switch device which can close, load and break the current under normal circuit condition, and can be closed, carrying and breaking the abnormal circuit condition (including short-circuit condition) under the specified time. Circuit breaker can be used to allocate electric energy, do not start asynchronous motors frequently, power lines and motors, such as protection, when they occur serious overload or short-circuit and undervoltage failure can automatically cut off the circuit, its function is equivalent to the fuse switch and the combination of thermal relays and so on. And after breaking the fault current generally does not need to change the spare part. At present, it has been widely used.

The circuit breaker is composed of a contact system, an arc extinguishing system, an operating mechanism, a tripping device and a shell. The circuit breaker is divided into miniature circuit breaker, plastic case circuit breaker and frame type circuit breaker according to its construction.

The role of Circuit breaker

Cut and connect the load circuit, and cut off the fault circuit, to prevent the accident from expanding, to ensure safe operation. and High-voltage circuit breakers to open 1500V, electric current 1500-2000a arc, these arcs can be stretched to 2m still continue to burn not extinguished. Therefore, Arc interrupter is a problem that must be solved by high voltage circuit breaker.

Low-voltage circuit breakers, also known as automatic air switches, can be used to connect and break load circuits, and to control motor motors that do not start frequently. It functions as a knife switch, over relay, lost voltage relays, thermal relays and leakage protector, such as electrical parts or all of the total function, is a low-voltage distribution network, an important protection of electrical appliances.

Low voltage circuit Breaker has many kinds of protection functions (overload, short circuit, undervoltage protection, etc.), adjustable action value, high breaking ability, convenient operation and safety, so it is widely used. Structure and working principle the low-voltage circuit breaker consists of operating mechanism, contact point, protection device (various kinds of tripping device), arc extinguishing system and so on.

The main contact point of the Low-voltage circuit breaker is operated by manual or electric switch. After the main contact is closed, the free tripping mechanism locks the main contact point on the closing position. The coil of the overcurrent tripping device and the heat-tripping device are in series with the main circuit, and the coil and power of the undervoltage tripping device are connected in parallel. When the circuit is short circuit or serious overload, the overcurrent tripping device, so that the free tripping mechanism action, the main contact disconnect the main circuit. When the circuit is overloaded, the heat of the hot-tripping device heats the bimetal sheet to bend, pushing the free tripping mechanism. When the circuit is under voltage, the armature of the Undervoltage release device is released. Also allows free tripping mechanism action. The shunt is used as a long-distance control, in the normal work, its coil is power off, in need of distance control, press the Start button, so that the coil power, the armature drive free tripping mechanism action, so that the main contact is broken.

Now has the electronic type, uses the transformer to collect each phase current size, compared with the setting value, when the current abnormality microprocessor sends the signal, causes the electronic tripping device to drive the operation mechanism movement.

1. The air switch is the air circuit breaker, which is opposite to the molded-shell circuit breaker, its role in the circuit is to connect, break and load rated working current and short-circuit, overload and other fault current, and can be overloaded in the line and load, short circuit, undervoltage and other problems, quickly divided off the road, the circuit for reliable protection.

2. Plastic case circuit breaker can automatically cut off the current, in general, when the current exceeds the set, it will automatically trigger protection. Plastic shells Here are used to use plastic insulators as housings for isolating conductors and grounding metal parts. The plastic case circuit breaker usually contains a thermal-magnetic stripping unit, while a large-type molded-case circuit breaker will be equipped with a solid-state stripping sensor.

Simply put, the circuit breaker is a switching device that can be simply imagined as a light switch. But the circuit breaker switch is much more complicated than the light switch, which contains many protective devices.