Generally speaking, of overload long delay, short circuit short delay and short circuit instantaneous action can realize selective protection. Most trunk lines (including the outlet end of the transformer) use it as the main protection switch.
Circuit breakers without short circuit short delay function (only two-stage protection of overload long delay and short circuit instantaneous action) cannot be used for selective protection, and they can only be used in branches. IEC92 “Marine Electrical” points out: Circuit breakers with three-stage protection focus on their operating short-circuit breaking capacity value, while circuit breakers used in branch lines should ensure that they have sufficient ultimate short-circuit breaking capacity value. Regardless of the type of circuit breaker, although they all have the two important technical indicators of Icu and Ics. However, as a circuit breaker used on a branch line, it can only meet the rated ultimate shor.
A circuit breaker is a basic low-voltage electrical appliance. It has overload, short circuit and undervoltage protection functions, and has the ability to protect lines and power supplies. The main technical indicators are rated voltage and rated current. Circuit breakers have different functions according to different applications, and there are many varieties and specifications, as well as many specific technical indicators.
Free tripping of circuit breakers: At any time during the closing process of the circuit breaker, if the protection action connects the tripping circuit, the circuit breaker can be completely and reliably disconnected. This is called free tripping. A circuit breaker with free tripping can ensure that the circuit breaker can be quickly disconnected when a short-circuit fault occurs during closing, which can avoid expanding the scope of the accident.
According to the number of poles: single pole, two poles, three poles and four poles; according to the installation method: plug-in type, fixed type and drawer type.
Post time: Jul-16-2024