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In this study, the most vital characteristic properties of induction motor, motor starting, maximum and nominal torque are analyzed for what are affected. For the analysis of torque, L type, T type and IEEE 112 equivalent circuit model is employed. Torque change is investigated with the help of codes developed in MATLAB to be used in electrical machines course. First, the slip-moment characteristic curve of the induction motor is divided into three working zones and it was determined which equivalent circuit model gave the best results in these study zones. Later, such parameters as stator and rotor resistance, stator and rotor reactance, magnetization reactance, core resistance and slip are researched for how torque values are affected from. The obtained values for each of the three equivalent circuit models are given and compared with experimental results. 50 HP squirrel cage induction motor parameters are used in analysis. In the analysis, the most influential parameters on the starting torque are found as rotor resistance and stator and rotor reactance. Change of other parameters’ impact ratio depending upon right proportion and inverse proportion is observed. When nominal torque variations are investigated, again rotor resistance is the most influential parameter and by selecting proper factor effecting rotor resistance during design, the result of acquiring desired rotor resistance is obtained. When the maximum torque variations are examined, it appears that the stator and rotor reactance values are effective. Starting, maximum and nominal torque expressions change with square of voltage alters the effect on them a lot. Therefore, triangle or star connection importance arises during machine design.

Abstract-This paper presents design and analysis performed for a dual winding electric machine. Windings of the machine are concentrated type so that electrical and magnetic isolation is maintained. For this reason, the proposed structure could be a reasonable candidate for fault tolerant applications. As required by some applications (electric accessory drive system (EADS) for hybrid electric vehicles), simultaneous motoring and generating operations can be implemented in a single housing of electric machine. Design considerations of the proposed electric machine are outlined in the paper. Also a comparison between distributed winding topology and concentrated winding topologies is performed. Finally experimental results discussed.

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This paper presents a new accessory drive system for hybrid electric vehicles (HEVs). This new concept involves a dual winding electric machine with simultaneous motor and generator functions. The electric machine provides power for all accessory loads such as the steering pump, compressors and 12 V loads. When the engine is off, the electric machine starts its motoring action and provides mechanical power to the accessory loads. Simultaneously, the generator windings provide power for the 12 V loads. The proposed structure could be a viable choice for fault-tolerant applications because of the concentrated winding type that maintains electrical and magnetic isolation. Design considerations of the proposed electric machine are outlined in the paper. The distributed winding topology and concentrated winding topologies are also compared. Analytical proof of magnetic decoupling is presented and experimentally verified. E. Mese et al.

The use of aluminum (Al) alloy substances is analyzed in this paper in order to obtain a lighter and less costly winding design without dimensional changes in electrical machines. The determination of aluminum alloy winding material, which has an electrical conductivity close to that of copper (Cu) but has a lower density, is the basis of this study. In this context, various aluminum alloy substances have been investigated. Windings with these aluminum alloy materials for a 300 kVA synchronous alternator have been modeled with the Ansys Maxwell 2D software program. The performances of tempered and annealed alloy windings have been analyzed with respect to that of a copper winding. The analysis results show that the aluminum winding losses are close to copper winding losses under nominal operating current values. Among the aluminum alloy winding models, aluminum 1350 and aluminum 2041 have the closest loss values. On the other hand, there is very little difference between aluminum alloy windings in terms of winding weight, while the weight of the aluminum winding is 70% lower compared with that of the copper winding. It is suggested to wind turbine manufacturers that windings be formed with the aluminum 1350 and aluminum 2041 series to provide performance comparable with that of copper windings.

Concentrated windings, in other words fractional slot windings are getting popular because of many proven advantages. In this study, a concentrated winding electric machine is designed for industrial applications. Although, in concentrated winding, mutual coupling between two adjacent coils is assumed to be zero, finite element analysis indicates that significant coupling may exist. Studies indicate that the coupling phenomena degrades fault tolerant capabilities of the concentrated winding structure. This paper, first, investigates the existence of mutual coupling then presents a new concentrated winding structure which still exploits benefits of conventional concentrated winding.