What does the elevator utility have?

If you are a shopping mall person, you will find that when we go shopping in shopping malls before, we usually find that no matter whether we are standing on the elevator, the speed of the elevator doesn't seem to have changed much. But if we go shopping, we will find that if we have no elevator in the shopping mall, we will find that the elevator is running very slowly. But if we stand on it, it will run fast, the same speed as the usual operation of the elevator.
Why is there a phenomenon like this? That's because he only used a very special accessory, which we call elevator electric appliances. After using it again, he can make the elevator energy saving. When the elevator doesn't have any heavy load, he will operate at a very slow speed. In this way, the consumption of electricity will be smaller and more electricity saving.
And if the top one has a weight, it will run at a normal speed. So when the elevator is used, the efficiency of electricity saving will be better for the shopping mall. When the whole shopping mall is running, many elevators are used, and the electricity saved by a month is very considerable. Therefore, elevators will install an elevator economizer.