下图为柳工ZL50G动力开关及动力切断选择开关，请简述图中1和2代表什么？<br /> <img src="https://nimg.ppkao.com/2019-05/wuacheng/2019051515031798192.jpg?sign=8c201bbf302f00a4c723ea6f3a87a998&t=62d74e15" />