Research Of Dynamic Balancing Technology For Dual-rotor System With Very Little Speed Difference Based On Virtual Instrument

Increasing in speed is the develop-trend of modern rotating machines, but it comes the higher request for dynamic balancing technique. The field whole-machine balancing method has practically been applied more and more widely because of its high precision, low cost and high efficiency.The dynamic balance for dual-rotor system such as the dual-rotor screw type centrifuge is a complex engineering problem, because its inner and outer rotors rotate with high speed of 3000-4000 rpm, but has a little rotating speed difference of 5-15 rpm between them. We can only get a beat signal formed by two vibration signals in field dynamic balance, and must obtain the unbalance values of both rotors from it. In this paper, the locomotion differential equation was established on the predigest model by using Newton Center of the Mass Motion Theorem, and select the whole machine balancing method without separate of the beat as the basic theory of dynamic balance for dual-rotor system with little speed difference .Different from the traditional dynamic balancing instruments, this paper combined the technique of virtual instruments with that of field whole machine dynamic balancing, and a dynamic balancing measuring and test system for dual-rotor system with little speed difference was developed using LabVIEW.The main function of the system is constitute of three parts: signal collection,signal processing and dynamic balancing calculation. The system used home-made data-collection card to collect the signal; used the vi of signal processing in LabVIEW to get the frequency compose of the signal, the magnitudes and the phases; used the mathematics tools of LabVIEW to finish the balancing calculation. The system has a friendly interface and can be used conveniently. It is a successful probe of VI technique applied in the dynamic balancing of dual-rotor system with very little speed difference.