New Generation Indoor 25KA High Voltage Vacuum AC Circuit Breaker

VF(R)-12 indoor embedded high-voltage alternating-current vacuum load switch-fuse combination (“vacuum load switch" )is a new generation vacuum switching equipment developed based on unique design ideas to meet the market demand. It is widely used for indoor armored air-insulated switch cabinets. In normal conditions, it can operate within its technical parameters in any grid of the specified voltage level safely and stably.

Technical Parameter

Transformer capacity and fuse selection

1.The fuse can cut off a large short-circuit current in less than 10 ms and its breaking current can be up to 50KA. Thus, it can protect the transformer most efectively.

2.In terms of match between the transformer and the fuse (Table 1), the potential surge current of the fuse must be considered. Thus, fusing current of the fuse must be 1.6 times of the rated value; designer must consider possible fluctuations of other parameters of the grid and reserve margins for them. If a fuse is selected for high-voltage motor protection, designer must consider frequency of start of the high-voltage motor because frequent starts of the high-voltage motor will result in the fuse's failure when timely cooling is not available.

Fuse selection