In the leakage cmcb box circuit breaker models will contain series, often see a variety of different types of series, so what does the different series represent? So let's first understand what a series is. Technically speaking, the "pole" of a circuit breaker refers to the pole used to break a wire, but not necessarily each pole provides protection. In simple terms, it refers to the number of lines disconnected at the same time. For example, 3P and 4P can disconnect 3 or 4 lines at the same time. For example: there are more 3P leakage circuit breakers installed in the general distribution box, and they are used to control the three phase lines of the three-phase AC circuit power supply. 4 p can also be used in three-phase circuit to control the three-phase ac power supply, control another very common to use as a normally open switch auxiliary contacts, when other controllers (such as PLC, etc.) need to collect the broken or circuit breaker, it can be the contact as of signal transfer points close to smell, all depends on the actual needs. Next, I will introduce the meaning of P and N in series, which can be discussed from two aspects:
I. Classification of products 1P, 2P, 1P+N, 3P,4P, 4P+N,P refers to the pole installed with protection (knife pole), N refers to the neutral line only installed with knife pole, no protection module installed. 2P and 1P+N are bipolar switches, while 4P and 3P+N are called quadrupole switches. 1P+N and 3P+N are not protected by the neutral line, so that the neutral line pole can operate with the phase line pole. Some products also divide 1P+N into two kinds: a kind of two module width, a kind of leakage circuit breaker only used a module width (small volume). 1P single-pole switch, 2P two-pole switch, 3P three-pole switch, 4P quadrupole switch, 1P+N- single-pole switch with zero terminal (zero line does not break), 3P+N- three-pole switch with zero terminal (zero line does not break).
Two, from the aspect of electrical technology, the choice of mcb box circuit breaker single-pole switch and two-pole switch, three-pole switch and four-stage switch is actually to see whether the neutral line of the line needs to be disconnected. It can be judged by the following points:
1. Consider maintenance safety: when the TT system needs maintenance, the neutral line is broken, so the bipolar and quadrupole switch is needed, TN system, after equielectric connection, except for special circumstances (see measures), there is no need to disconnect the neutral line, generally choose single pole and three pole. Quadrupole switches can be used sparingly because of the danger of "zero break".
2. When there are two power supplies, check whether the two grounding systems need to be isolated. In addition, 1P+N, 3P+N, 2P and 4P are all regarded as bipolar and quadrupole switches in terms of electricity. When it is determined that the neutral line needs to be disconnected but the current of the neutral line cannot exceed the phase line, 1P+N and 3P+N can be selected in consideration of cost saving. If the neutral line current is likely to exceed the phase line (harmonics, etc.), the 2P, 4P1P (1 pole) switch needs to be selected: there is only one connection and only one phase line can be disconnected. This switch is suitable for controlling a phase "fire" line. 2P (3 pole) switch: there are two terminals, one connecting phase line and one connecting zero line, this switch is suitable for controlling one phase one zero. 3P (3 pole) switch: there are three terminals, three are connected with "fire" line, this switch is suitable for controlling three-phase 380V voltage line. 4P (4 pole) switch: there are four terminals, three are connected with "fire" line, a zero line, this switch is suitable for the control of three phase four wire system line. Finally, the problem is that the same series of leakage circuit breakers are found in the discussion of the above series, but there may be some with N, such as 4P and 3P+N are four levels, then what is the difference between them, and how to choose? According to the above discussion, both of them are four-stage switches, but the difference is that the N-line of 4P has protection, while the N-line of 3P+N has no protection. Meanwhile, the N-line of 3P+N has no overload or short-circuit tripping coil, so it has no protection effect. There is a mechanical relationship between the N-pole line and the other three stages.
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