The balancing machine is a measuring tool used to balance rotating mechanical parts, such as electric motors, fans, turbines, disc brakes, disk drives, propellers and pumps used for rotors. The balancing machine is usually composed of two rigid bases, with suspension and bearings on the top, to support the installation platform. The tested workpiece is fixed on the platform with bolts and rotated by belt drive, air drive or end drive device. As the part rotates, vibration uses sensors to detect impurities in the suspension and uses this information to determine the amount of unbalance in the part. In addition to phase information, the balancing machine can also determine whether to increase or decrease weights to balance the number and position of parts.

Dynamic balancing machines are classified into two types according to the support mode: hard support balancing machine and soft support balancing machine. The difference between them is suspension rather than bearing. In the hard support balancing machine, balance at a frequency lower than the resonance frequency of the suspension. In the soft support balancing machine, balance at a frequency higher than the resonance frequency of the suspension. Both types of machines have various advantages and disadvantages. Hard supported balancing machines are generally more versatile and can handle parts with large weight variations because hard bearing machines are measuring centrifugal effects and require only one calibration. Only five geometric dimensions need to be input into the measuring unit to use the machine. Therefore, it is very suitable for small and medium-sized batch production and maintenance workshops, and the soft support balance has high dynamic balance correction accuracy.