The load switch, as the core component of a high-voltage ring main unit, is generally equipped with a simple arc-extinguishing device but features a relatively simple structure.
Its working process is as follows: During opening operation, driven by the opening spring, the main shaft rotates clockwise. On one hand, it drives the piston to move upward through the crank-slider mechanism to compress the gas; on the other hand, through the transmission system composed of two sets of four-bar linkages, the main blade opens first, then pushes the arc-extinguishing blade to open the arcing contacts. The compressed air in the cylinder blows out the electric arc through the nozzle.
The load switch is a type of switching device between a circuit breaker and an isolating switch. Equipped with a simple arc-extinguishing device, it can interrupt rated load current and a certain degree of overload current, but cannot interrupt short-circuit current. According to the operating voltage, it is classified into high-voltage load switches and low-voltage load switches.
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