A circuit breaker is an electrical switch designed to protect an electrical circuit from damage caused by overcurrent, short circuits, or other faults. Here is a detailed introduction:
Working Principle
Under normal operating conditions, the moving and stationary contacts of the circuit breaker are closed, allowing current to flow through the circuit to ensure the normal power supply of the electrical system. When faults such as overload or short - circuit occur in the circuit, the fault current causes the release of the circuit breaker to operate. The release uses a mechanical device to separate the moving contact from the stationary contact, thus cutting off the circuit and protecting the electrical equipment and lines.
Structural Components
- Contact System: It is the execution component that connects and disconnects the circuit, usually consisting of a moving contact and a stationary contact.
- Arc - Quenching System: Used to extinguish the arc generated when the circuit breaker breaks the circuit, preventing the arc from continuing to burn and causing faults such as contact damage and inter - phase short - circuit.
- Release: It is the protection component of the circuit breaker, which can detect parameters such as current and voltage in the circuit. When abnormalities occur, it sends a signal to trip the circuit breaker.
- Operating Mechanism: Used to control the closing and opening operations of the circuit breaker, which can be manual, electric, or pneumatic.
Classification
- By voltage level, it can be divided into high - voltage circuit breakers, medium - voltage circuit breakers, and low - voltage circuit breakers.
- By arc - quenching medium, it can be divided into oil - circuit breakers, air - circuit breakers, sulfur - hexafluoride circuit breakers, vacuum circuit breakers, etc.
- By purpose, it can be divided into circuit breakers for power distribution, circuit breakers for motor protection, circuit breakers for lighting, etc.
Application Areas
- In the power system, it is used in power plants, substations, and transmission lines to control and protect power equipment, ensuring the safe and stable operation of the power system.
- In the industrial field, it is used in the electrical systems of factories to protect equipment such as motors and transformers from damage caused by faults such as overload and short - circuit.
- In the construction field, it is used in the power distribution systems of buildings to protect circuits such as lighting and sockets, preventing accidents such as electrical fires.
Main Parameters
- Rated voltage: It refers to the voltage level that the circuit breaker can withstand during normal operation.
- Rated current: It refers to the maximum current that the circuit breaker can allow to pass through for a long time under specified conditions.
- Short - circuit breaking capacity: It refers to the maximum short - circuit current value that the circuit breaker can reliably break under specified conditions.
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