What causes balance machine accuracy

What causes balance accuracy?
(1) balance of speed and the rotational speed is inconsistent, resulting in decreased balance precision. For example: a number belongs to the second-order critical speed of rotor interference of rotor, due to the limited speed balancing machine itself, the rotor using the process balance, you cannot effectively prevent rotor imbalance caused by the deformation at high speed.
(2) the propshaft balancing machines (in particular high speed vertical balancing machines) are expensive.
(3) the balancing of the rotor in the dynamic balancing machine, installed after balancing accuracy is difficult to guarantee. Because moving balance Shi of supports conditions different Yu rotor in actual work conditions Xia of supports conditions, and rotor with balance device Zhijian of tie also different Yu rotor and its itself hinge Zhijian of tie conditions, even factory Qian has in moving balance machine Shang reached high precision balance of rotor, after transport, and again Assembly, process, balance precision in using Qian inevitably has declined, dang in work speed Xia running Shi, still may produced not allows of vibration.