There are many Roots blowers with a belt rotation, the belt rotation is a whole, a mounted on the fan shaft, a mounted on the motor shaft. The basic requirements for installing such belt rotation are: first, the motor shaft and fan shaft must be strictly parallel, and the belt rotation is not allowed to be skewed or oscillated. Inclination shall not exceed 0.2%. Secondly, when the two pulleys are of the same width, their end surfaces should be located on the same plane; if the pulleys are of different widths, the middle planes of the two side pulleys should coincide. Third, it should be that the degree of tensioning of the drive belt can ensure that there is enough friction on the contact surface of the belt and pulley to obtain a high transmission efficiency.