久久精品无码av,国产欧美日韩视频一区二区三区,久久精品国产亚洲av品善,成人天堂噜噜噜 ,日日碰狠狠躁久久躁一区二区

It mainly refers to diesel generators, gasoline generators which used as standby power equipment when utility interrupt in the earlier time that UPS is not appeared. However, after UPS appears, it has more advantages, like play dynamic response quickly, adjust output stability, eliminate the absorption power external adverse impact, protect the electrical equipment. Therefore, UPS gradually occupy a larger proportion in contemporary standby power.