I've covered a lot of moulded case circuit breakers, do you know how a moulded case circuit breaker works? Please investigate this issue with the web editor.

Moulded case circuit breakers are generally composed of contactors, arc extinguishing systems, operating mechanisms, decouplers and housings.

In the case of a short circuit, the magnetic field that generates a high current (generally 10 to 12 times) will overcome the reaction spring, the tripping device pulls the operating mechanism into action and the switch trips instantly. If there is an overload, the current will become high, the heat generation will become violent and the bimetal will deform to some extent, causing the mechanism to act. Yes, please note that the higher the current, the shorter the operating time.

Electrical has an electronic type of circuit breaker that uses a transformer to collect the magnitude of the current in each phase, compare it with the set value, and in the event of a current abnormality the microprocessor sends a signal and the electronic tripping device activates the operating mechanism.

The function of the moulded case circuit breaker is to cut off and switch on the load circuit as well as to cut off faulty circuits to prevent the expansion of accidents and to ensure safe operation. High voltage circuit breakers must cut off arcs of 1500V and currents of 1500A-2000A, which do not continue to burn out even if they extend to 2m. Therefore, arc extinguishing is a major problem that must be solved for high-voltage circuit breakers.

The principle of the arc extinguishing coil is mainly on the one hand cooling the arc to weaken the heat free, on the other hand blowing the arc to lengthen the arc to enhance the composite and diffusion of charged particles, while blowing away the charged particles in the arc gap, quickly restore the insulation strength of the medium.

Low voltage moulded case circuit breakers, also known as automatic air switches, are used to switch on and off load circuits, as well as to control motors that are not frequently started. Its function is equivalent to the sum of some or all of the functions of thyristors, overcurrent relays, undervoltage relays, thermal relays, earth leakage protectors and other electrical appliances, and is an important protective appliance for low-voltage distribution networks.

Low-voltage moulded case circuit breakers have a variety of protection functions such as overload, short-circuit and under-voltage protection, with the advantages of adjustable working values, strong breaking capacity, easy operation and safety, etc. They are now widely used. Structure and working principle of low-voltage circuit breaker by the operating mechanism, contacts, protection devices (a variety of decoupling devices), arc extinguishing system and other components.

The main contact of the low-voltage moulded case circuit breaker is manually operated or electrically switched on. After the main contact is closed, the free release mechanism locks the main contact in the on position. The coil of the overcurrent trip and the thermal element of the thermal trip are connected in series with the main circuit and the coil of the undervoltage trip is connected in parallel with the power supply. When the circuit is short-circuited or severely overloaded, the armature of the overcurrent tripping device adsorbs, the free tripping mechanism acts and the main contact cuts off the main circuit. After the circuit is overloaded, the thermal element of the thermal release device heats up and bends towards the bimetal, and the free release mechanism starts. When there is insufficient voltage in the circuit, the armature of the undervoltage release mechanism is released. The free buckling mechanism is also activated. The branch decoupling device is used for remote control, the coil is switched off during normal operation, when distance control is required the start button is pressed to switch on the coil and the armature activates the free decoupling mechanism to close the main contacts.