A circuit breaker is a switch that can connect and disconnect a circuit. According to its different functions, it can be divided into air circuit breakers and gas-insulated metal-enclosed switchgear (GIS).
The advantages of the circuit breaker: simple structure, cheap price, can greatly improve the construction quality of the project; large breaking capacity, strong overload capacity, infrequent connection and breaking of the line; complete protection function, can quickly cut off the circuit in a very short time .
Disadvantages of circuit breakers: large heat and high arc light are generated during short circuit; frequent operations cannot be performed; sufficient time is required for the metal in the fuse to return to the melting point.
When the circuit breaker is converted from an air switch to a GIS, the following regulations shall be met:
1) The circuit breaker must be well grounded during installation and use;
2) Good insulation should be maintained between the GIS switchgear and the ground;
3) The installation site should have good drainage facilities.
Function
A circuit breaker is a switch used to turn on and off a circuit, and usually has the function of turning on and off a circuit, and also has functions such as short circuit protection and overload protection. At the same time, its breaking ability is very strong, and it can quickly cut off the circuit in a very short time.
1. As a low-voltage power distribution device, the circuit breaker has the function of protecting the circuit from overload, short circuit and undervoltage.
2. The circuit breaker has the advantages of strong ability to cut off the current and quick action; it also has the short-circuit protection function of the short-circuit current of one-phase fracture.
3. As a low-voltage power distribution device, the circuit breaker can close or disconnect the circuit of the normal working power supply within the specified time; it can continuously supply power to the line without failure, and can also be used as a motor stator insulation and circuit when necessary. Auxiliary circuits for various electrical appliances.
Install
1. Before installation, check the appearance of the circuit breaker for cracks, then open the end cover of the circuit breaker, and check the identification and nameplate on the end cover. Check against the model specified in the product manual.
2. The installation of the circuit breaker should meet the design requirements, and should be consistent with the installation position of other electrical equipment on the power distribution panel or power distribution device. It is not permitted to install on or pass near other electrical equipment and appliances (switches).
3. The circuit breaker and its accessories must be reliably grounded. For multi-layer wiring, the top socket and cable shielding layer should also be grounded.
4. The operating mechanism should be subjected to a load test before dismantling to ensure that its action is flexible and reliable before dismantling. Check whether the wiring is correct before dismantling, otherwise it cannot be dismantled blindly.
5. When the circuit breaker is installed in a metal box, the fastening bolts in the box are not allowed to loosen; the connection between the box fixing bolts and the thread should be reliable; the fixing nuts should be anti-loosening screws; the screw holes should be drilled mechanically ;
Protect
When the system fails, such as motor overload, short circuit, etc., major accidents and serious consequences can be avoided, which requires the use of circuit breakers to protect electrical equipment or circuits from damage. However, the circuit breaker cannot truly achieve “maintenance-free”. In some cases, certain maintenance is still required.
1. When an overcurrent trip occurs during the operation of the circuit breaker, check whether other electrical appliances are in good working condition;
2. Check the operation of the leakage protection device, and it should operate under normal working conditions;
3. When the electric operating mechanism fails, check the coordination between the electric operating mechanism and the circuit breaker;
4. When a short-circuit fault occurs in the line, the power supply should be disconnected;
5. Due to the aging of the internal insulation of the circuit breaker after long-term operation. Therefore, the circuit breaker should be regularly maintained.
Precautions
1. The operating mechanism must be reliable to avoid accidents. There should be obvious indicator indications and actions for the action of each component in the mechanism, and malfunctions should be prevented.
2. For a circuit breaker in operation, even if its handle is in the tripping state, arcing may still occur in the contacts or in the opening and closing circuits. Care must be taken to prevent misoperation during operation.
3. When the circuit breaker operates (especially when cutting off a large current), it cannot be pulled on forcibly, so as not to damage the electrical components.
4. The circuit breaker should always check its opening and closing contact conditions to avoid overvoltage or undervoltage faults.
5. When a fault trip occurs, try to restore the cut off power supply first.
Post time: Feb-16-2023