The difference between fuses and circuit breakers

The function of circuit breaker: the function of circuit breaker is to cut off and connect the load circuit, as well as cut off the fault circuit, to prevent the expansion of accidents, to ensure safe operation.

Role is the role of the fuse, fuse the itself as the melt, when the current is too high or over load current by fusing itself prevent damage of the circuit of electrical components, this with open circuit breaking current is two kinds of difference and its role can be commonly used fuse to understand with our home, and circuit breaker, basic is used as the master switch. The fuse is installed in the circuit.

The difference between fuse and circuit breaker: the same is to achieve short circuit protection, the principle of fuse is to use the current flowing through the conductor will make the conductor heat, to reach the melting point of the conductor after the conductor melts, so the circuit protection with electrical appliances and the line is not burned out. It is an accumulation of heat, so it can also achieve overload protection. Once the melt burns out, the melt must be replaced.

Fuses and circuit breakers performance comparison:

Fuse:

1. Main advantages and characteristics of fuse

1) Good selectivity. As long as the rated current of the upper and lower fuses meets the requirements of 1.6:1 overcurrent selection ratio stipulated in national and IEC standards, that is, the rated current of the upper fuses is not less than 1.6 times that of the lower fuses, the upper and lower fuses can be regarded as having selective cut-off fault current.

2) Good current limiting characteristics, high breaking ability:

3) Relatively small size;

4) The price is lower.

2. Main disadvantages and weaknesses of fuses

1). Fuse body must be replaced after fault fuse;

2) Single protection function, only a section of over current inverse time limit feature, overload, short circuit and grounding fault are used for protection;

3) When a phase fuse occurs, the three-phase motor will lead to two phase operation of the adverse consequences, of course, the fuse with alarm signal to compensate, phase fuse can be disconnected three phases

; 4) Remote control can not be achieved, it is possible to combine with electric knife switch and switch.

Non-selective circuit breaker:

1. Main advantages and features

1) After the fault is disconnected, it can be reset by hand without replacing components, unless maintenance is needed after cutting off the large short-circuit current;

2) Long delay trip and instantaneous current trip with reverse time characteristics of two protection functions, respectively for overload and short circuit protection, each play its own role;

3) Remote control can be realized when electrified operation mechanism.

2. Major weaknesses and weaknesses

1) It is difficult to achieve selective cutting between the upper and lower non-selective circuit breakers. When the fault current is large, it is easy to lead to instantaneous disconnection of the upper and lower circuit breakers;

2) The relative price is slightly higher;

3) Part of the breaker breaking capacity is small, such as the lower rated current of the breaker installed near the position of large capacity transformer, will make the breaking capacity is not enough. Existing products with high performance can be satisfied, but the price is higher.

Selective circuit breaker:

1. Main advantages and features

1) Has the advantages of non-selective circuit breaker;

2) with multiple protection function, with long time delay, instantaneous, short time delay, and ground fault (including zero sequence current and residual current protection) protection, overload respectively, cut-off time delay and large short-circuit current instantaneous movement and ground fault protection, protection of high sensitivity, adjust various parameters is convenient, easy to satisfy the distribution line protection requirements. In addition, can be cascaded protection function, with better selective action performance;

3) Nowadays, most products have the characteristics of intelligence. In addition to the protection function, there are also electric quantity measurement, fault recording, and communication excuse to realize the centralized monitoring and management of distribution devices and systems.

2. Main problems

1) The price is very high, so it should only be used in the first end of the distribution line and the branch line of special important places

2) Large size.