Dynamic State of Low Power Asynchronous Motors in Direct-on-Line Starting


The research opportunity is explained by the results obtained in modelling and simulation of asynchronous motors, in the purpose of increasing their technical and economic performances when they operate in dynamic states. The study of the dynamic state is compulsory for low and very low power asynchronous motors which are used for driving industrial robots. In order to have simulation results, which are to be close to reality (those established experimentally), it is necessary to know the main inductance and the leakage inductance of the windings, their dependence upon the machine load, so upon the magnetic saturation. In this paper there are presented results, simulations and experimental tests are carried out in order to establish the errors which occur, for correcting the mathematical model used. With the help of the mathematical model presented in this paper, much complex dynamic states can also be studied, caused by the variation of the voltage, of the resistant torque, of the inertia moment etc. The starting characteristics have been computed considering magnetic saturation and current pressing, the results being: starting current Ip=4.208*IN, starting time tp=0.17s. It is considered that this study of asynchronous motor starting is justified, with an eye to obtaining some indications for their optimum construction and operation. images