Difference between load break switch and circuit breaker

Aload breakswitch is an electrical appliance between ahigh-voltage circuit breakerand ahigh-voltage isolation switch. In this article, let’s take a look at the working principle of  load break switch and the difference between load break switch and circuit breaker.

Working principle of load break switch

The high-voltageload break switchworks similarly to a circuit breaker. Generally, the installation of simple arc extinguishing device, but its structure is relatively simple. The picture shows the high-pressure load break switch of compressed air. Its working process is: when the brake is opened, under the action of the opening spring, the spindle is rotated clockwise. On the one hand, the piston moves upward through the crank slider mechanism to compress the gas; On the one hand, through the transmission system composed of two sets of four-link mechanism, the main knife is opened first, and then the arc breaker is pushed to open the arc breaker contact, and the compressed air in the cylinder is blown out through the nozzle to discharge the arc.

When closing, the main cutter and the arc breaker turn clockwise at the same time through the spindle and the transmission system, and the arc breaker contact is closed first. The spindle continues to rotate so that the main contact closes later. During the closing process, the opening spring simultaneously stores energy. Because load break switch can not break the short circuit current, it is often used with the current limiting high voltage fuse. The current limiting function of the current limiting fuse not only completes the task of breaking the circuit, but also significantly reduces the influence of thermal and electric power caused by short circuit current.

Therefore, load break switch is the switching appliance between circuit breaker and isolation switch. It has a simple arc extinguishing device, which can cut off the rated load current and a certain overload current, but can not cut off the short circuit current.

The difference between load break switches and circuit breakers

From a traditional perspective, load break switches are very different from circuit breakers. Load break switch is mainly used to break and close the load current. It can be used with high-voltage fuses to replace high-priced circuit breakers and cut off the fault current, that is, the short-circuit current. It is determined that the arc extinguishing function of the load break switch is weak, which reduces the manufacturing cost. It is precisely because the traditional load break switch is not used to cut off the difference between the fault current fuse and the circuit breaker, there is no need to connect the protection device and the automatic device, so most of the load break switch is manually operated. Cannot be operated electrically. In the design of the circuit breaker, it is considered that not only can the load current be turned on and off.

Switches specially designed to handle current (fault current, rated current) are circuit breakers, and the level of break insulation of circuit breakers is very low, so the ability to handle overvoltage is very weak. The switch specially designed to deal with the voltage (the insulation level of the fracture is very high, which can deal with the high fracture voltage withstand value) is the isolation switch, commonly known as the tool brake. Load break switch is a switch between the two that can handle current (rated current) and voltage (the insulation level of the break is higher than the circuit breaker, but lower than the isolation switch), but although the load break switch can break and close the rated current, closing the short circuit current, but it is strictly prohibited to break the short circuit current.

This is the working principle of load break switch and the difference between load break switch and circuit breaker.