A circuit breaker is a switching device capable of closing, carrying and breaking current under normal circuit conditions and capable of engaging and driving current under abnormal circuit conditions (including short circuit conditions) for a specified period of time. Circuit breakers can be used to distribute power, Circuit Breakers not frequently start the asynchronous motor, the power lines and motors to protect, when they have a serious overload or short circuit and undervoltage failure can automatically cut off the circuit, Circuit Breakers its function is equivalent to fuse switch And the combination of overheat relay and so on. And after breaking the fault current generally do not need to change the parts. At present, Circuit Breakers has been widely used.
Circuit breakers generally by the contact system, arc system, operating mechanism, release, shell and so on. The circuit breaker is divided into miniature circuit breakers, Circuit Breakers molded case circuit breakers and frame type circuit breakers according to their structure.
Cut off and connected to the load circuit, Circuit Breakers and cut off the fault circuit to prevent accidents to ensure safe operation. And high-voltage circuit breakers to break 1500V, current 1500-2000A of the arc, these arc can be stretched to 2m still continue to burn is not extinguished. Circuit Breakers So the arc is high voltage circuit breaker must solve the problem.
Low-voltage circuit breakers, also known as automatic air switches, can be used to turn on and off the load circuit, can also be used to control the motor is not frequent start. Circuit Breakers It is equivalent to the knife switch, over-current relay, loss of stress relays, Circuit Breakers thermal relays and leakage protector and other electrical parts of the sum of all the functions of low-voltage distribution network is an important protection of electrical appliances.
Low-voltage circuit breakers with a variety of protection functions (overload, short circuit, under voltage protection, etc.), adjustable action value, Circuit Breakers breaking capacity, easy operation, Circuit Breakers security, etc., so now widely used. Structure and working principle Low-voltage circuit breaker by the operating mechanism, contacts, protection devices (various releases), arc system and other components.
Low-voltage circuit breaker main contact is by manual operation or electric closing. When the main contact is closed, the free trip mechanism locks the main contact in the closing position. The coil of the overcurrent release and the thermal element of the thermal release are connected in series with the main circuit, and the coil of the undervoltage release and the power supply are connected in parallel. Circuit Breakers When the circuit short circuit or serious overload, the overcurrent release of the armature pull, so that the free trip mechanism, the main contact disconnect the main circuit. When the circuit is overloaded, the thermal element of the thermal release heats the bimetallic sheet to bend and push the free trip mechanism. When the circuit is undervoltage, Circuit Breakers the armature of the undervoltage release is released. Also let the free trip mechanism action. Shunt release is used as a remote control, in normal operation, the coil is power, in the need for distance control, Circuit Breakers press the start button, the coil power, armature driven free trip mechanism, so that the main touch Point off.
Now there are electronic type, Circuit Breakers the use of the transformer to collect the current size of each phase, compared with the set value, when the current is abnormal when the microprocessor sends a signal, so that the electronic release device to drive the action.