According to the structure of the circuit breaker classification, there are universal type, plastic shell type, plastic case circuit breaker, which is suitable for rated voltage 690V, frequency 50/60Hz, rated current 16 to 1600A distribution system or as a transformer, motor, capacitor and other protection equipment. Mainly to distribute electric energy, do the branch and electrical equipment overload, short circuit, leakage point and under-voltage protection, can also be used for line and electrical equipment is not frequent conversion. It is widely used in industry and agriculture, transportation, mining, civil construction and national defense and other departments, the transmission and distribution of power, circuit control and protection plays a great role, is a large usage, a wide range of products. Because users do not understand the characteristics and technical requirements of MCCB deeply or comprehensively, some concepts are easy to be confused with each other, and there are often some errors and misunderstandings in the practical application. The important parameters that the user needs to pay attention to when choosing and using the MCCB are introduced in detail. Now, the description of the shell frame level of the breaker is used to help the user reasonably choose to use the MCCB.
Circuit breaker shell bracket grade
Circuit breaker housing frame rating is the rated current of the maximum trip that can be mounted on a frame and plastic housing of the same basic size.
The rated current of circuit breaker is the current that the trip in the circuit breaker can pass for a long time, also known as the rated current of circuit breaker trip.
There are a variety of shell frame rating current in the same series, and a variety of rated current in the same shell frame rating current. For example, there are 16A, 20A, 25A, 32A, 40A, 50A, 63A, 80A and 100A rated current in the 100A shell and frame rating; There are 100A, 125A, 160A, 180A, 200A, 225A rated current in 225A shell and frame class. There are 100A rated current in both 100A and 225A shell bracket grades, but the size, shape and breaking capacity of the circuit breaker are different. Therefore, the type should be filled in completely when selecting, that is, the rated current of the circuit breaker within the rated current of the specific shell bracket grade. The rated current classification is selected according to the priority coefficient of (1.25) : on the one hand, it meets and meets the needs of the maximum rated current of the circuit and electrical components; The other is for standardization, in order to obtain the best use of wire and processing benefits. Therefore, the grades it provides are: 3(6), 8, 10, 12.5, 16,20, 25, 32, 40, 50, 63, 80,100, 125, 160, 200, 250, 315, 400A, etc. Because of this regulation, when the calculated load of the line is 90A, only 100A specification can be selected, so its protection performance is affected to a certain extent.
Tripper current setting is when the tripper is adjusted to the operating current value. It refers to the rated current In multiple, is the value of the action current, for example: overcurrent set to 1.2, 1.3, 5, 10 times the current, is written IR =1.2In, 1.3In, 5In, 10In, etc. Now some electronic trippers, its overload and long delay rated current is adjustable, the adjusted current, in fact, is still the rated current, is the maximum current that can be passed for a long time.
The rated working current is the actual working current of the circuit breaker at a certain working voltage when the auxiliary contacts (accessories) are installed. The current is 3A or 6A, which is used to control and protect the circuit.
Post time: Jul-16-2021