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Easybom has collected rich information and conducted a series of detailed research on the circuit breaker which is widely used.
The circuit breaker is a switch device capable of turning off, carrying and breakingcurrents in normal circuits and turning off, carrying and breaking in abnormal circuits within a specified time. Circuit breakers can be classified into high-voltage circuit breakers and low-voltage circuit breakers. The division of high and low voltage boundary is obscure.
Easybom has found that the circuit breakers is a widely used component which can be used to distribute electricity, start asynchronous motor, and protect power line and motor. It automatically cuts off circuit when serious overload, short circuit or other failures occur. In this situation, its function is equivalent to the combination of fuse switch and overheat relay. And it is unnecessary to change parts after breaking the fault current.
After the study on the circuit breaker carried out by Easybom and a combination of the information provided by related experts, the working principle of the circuit breaker has come to a conclusion. Easybom has analyzed the working principle of the high-voltage circuit breaker and low –voltage circuit breaker respectively.
The working principle of high-voltage circuit breaker analyzed by Easybom
When a circuit is short-circuited, the large current (generally 10 to 12 times) generates a magnetic field which overcomes the reaction force spring, the trip unit pulls the operating mechanism, and the switch trips instantly. When overloaded, the current becomes larger, the heat increases, and the bimetallic deform to a certain extent to promote the mechanism move (the greater the current, the shorter the action time).
If there is an electronic type, the transformer is used to collect the current size of each phase. Compared with the set value, when the current is abnormal, the microprocessor signals, causing the electronic stripper to drive the operating mechanism.
The circuit breaker is used for preventing accident expansion and ensuring safe operation by cutting off and turning on the load circuit and cutting off the fault circuit.
Oh no! What if we need to make a circuit break? Well, it has to be high-voltage and able to handle 500V and 1,500-2,000A. This arc can stretch up to two meters without being extinguished.
As a result, arc extinguishing is a problem that must be solved in a high-voltage circuit breaker.
The working principle of low-voltage circuit breaker analyzed by Easybom
The low-voltage circuit breakers, also known as automatic air switches, are applied to connect and break load circuits, and control motors operating infrequently. The low-voltage circuit breakers can be operated conveniently, and have high breaking capacity and various protection functions so they are widely used.
Low-voltage circuit breakers have a manual or electrically operated main contact. Once the main contact is closed, it stays in that position thanks to the free trip mechanism.
When the circuit is short-circuited, severely overloaded, or somehow damaged, the overcurrent protective device releases itself. In this way, the main contact disconnects the main circuit.
The thermal trip unit has a heating element that is activated when the circuit becomes overloaded. When the under-voltage circuit is activated, the armature releases. When the free trip mechanism is active, it is also cut off when not in use for distance control. The start button can be used to make the coil energized so it can work for appropriate distance control.