Abstract
The article presents the results of work on an effective numerical study of selected transient states of a low-power electrical machine. The object of detailed research was a synchronized squirrel-cage induction motor. Its ability to work at a synchronous speed was enabled by obtaining reluctance torque, caused by an imposed asymmetry between the direct and quadrature reluctances of the rotor. The difference between the reluctances was achieved by changing the rotor geometry by milling additional deep grooves. The modifications of the rotor did not damage the continuity of the rotor cage. Imposed lots were arranged symmetrically around the rotor circumference. In order to study the performance of the modified motor, a parameterized, numerical model of the machine was developed to evaluate the impact of the geometry of the slots. The developed three dimensional (3D) model of the electromagnetic phenomena in the studied magnetic circuit employs the finite element method (FEM). The model takes into account the saturation of the machine’s magnetic circuit and the skew of the rotor cage bars as well as the mechanical equilibrium of the terrain system including the moment of inertia and frictional torque in the bearings as well as the load torque resulting from the operation of the internal fan. The simulation study concerned the starting process of the machine under different values of the load. The influence of the supply voltage phase angle at the moment of start-up and the initial position of the rotor in relation to the stator was investigated. In order to calibrate the model, tests of the physical object were performed. The corrections introduced concerned the magnetization characteristics of the magnetic circuit. The results obtained confirm the correctness of the adopted strategy of testing the operational properties of the considered engine.
Highlights
The ever-increasing cost of electricity is pushing users to look for devices that are as efficient as possible
It was assumed that: The modified motor should be capable of starting without the use of any additional systems or special starting procedures, at an external load torque of no less than 40% of the rated torque of the induction motor; The motor, when loaded with the above-mentioned static torque, should fall into synchronism; and Each time the motor is overloaded, it should pass into an asynchronous operation mode and its unloading should result in the return to a synchronous operation mode
It has been shown that the synergy of numerical research and physical experiments should be a trend in the modern methodology of electrical machinery production
Summary
The ever-increasing cost of electricity is pushing users to look for devices that are as efficient as possible. The main disadvantage of this approach is the still existing inability to consider the influence of mechanical technology and thermal processing of details on the final parameters of the manufactured machine. Such prototyping allows one to limit the number of physical models of the built device. The results of the experiments presented in the latter part of this paper concern both the tests carried out with the physical object before and after the introduction of the modifications as well as the results of the simulation studies using the proprietary numerical model of the tested motor employing the 3D FEM. It has been shown that the synergy of numerical research and physical experiments should be a trend in the modern methodology of electrical machinery production
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
