Differences And Characteristics Of Fuses And Circuit Breakers

Differences and Characteristics of Fuses and Circuit BreakersFuse

Fuse

(1) The main advantages and characteristics of fuses.

①Selectiveness is good. As long as the rated current of the fuse link of the upper and lower fuses complies with the requirement of the overcurrent selection ratio of 1.6:1 stipulated by the national standard and the IEC standard, that is, the rated current of the upper and lower fuse links is not less than 1.6 back of the value of the upper and lower fuses, it is regarded as the upper and lower fault current. , which can be selectively cut off.

②Good current limiting characteristics and high breaking capacity.

③ Relatively small size.

④ The price is cheap.

(2) The main shortcomings and weaknesses of the fuse.

①After the fault is blown, the fuse must be replaced.

②The protection function is single, only the inverse time characteristic of overcurrent, overload, short circuit and ground fault.

③ When one-phase fuse occurs, the three-phase motor will cause adverse consequences of two-phase operation. Of course, fuses with alarm signals can make up for it, and one-phase fuses can disconnect three-phase.

④The remote control cannot be realized, it needs to be combined with the electric knife switch and switch to realize it.

Non-selective circuit breaker.

(1) Main advantages and features.

①After the fault is disconnected, unless maintenance is required after cutting off the large short-circuit current, it can be manually reset without replacing the components.

②The long-delay release and instantaneous current release with inverse time characteristics are used for overload and short-circuit protection respectively, and each performs its own duties.

③The live operating mechanism can realize remote control.

(2) Major shortcomings and weaknesses.

①Selective disconnection is difficult to achieve between upper and lower and non-selective circuit breakers. When the fault current is large, it is easy to cause the upper and lower and circuit breakers to be disconnected instantaneously.

②The price is slightly higher.

③ Some circuit breakers have smaller breaking capacity. For example, when a circuit breaker with a lower rated current is installed close to a large capacity transformer, the breaking capacity will be insufficient. At present, products with high breaking capacity can satisfy, but the price is higher.

Selected circuit breaker.

(1) Main advantages and features.

① It has the above advantages of non-selective circuit breakers.

②Have a variety of protection functions, including long delay, instantaneous, short delay and ground fault protection, respectively realize overload, open circuit delay, instantaneous movement of large short-circuit current and ground fault imitation, high degree of protection, and convenient adjustment of each parameter.

③ At present, most products have intelligent features. In addition to the protection function, there are also power measurement, fault recording and communication interface to realize centralized monitoring and management of power distribution devices and systems.

(2) The main problem.

① The price is very high, and it is only suitable for one end of the distribution line and the sub-trunk in important places.

②Large size