RESULTS OF VARIANT CALCULATIONS OF MAGNETIC FIELD, CURRENTS, LOSSES, AND LEAKAGE REACTANCE IN THE BAR-TYPE ARMATURE WINDING OF INDIRECTLY COOLED AC ELECTRICAL MACHINE BASED ON FIELD-CIRCUIT FORMULATION

The article presents the results of variant calculations of magnetic field, currents, losses, and leakage reactances in the slot parts of bar-type armature winding of indirectly cooled AC electrical machines performed on the base of finite element analysis of AC magnetic field problem in a 2D formulation considering electric circuit. The implemented method accounts for the design and transposition of the strands of the bars along the length of the armature slot part, the location of the bars in the armature slots, the features of the indirectly cooled machine slot geometry and the diagram of armature winding connections. The method is based on straighten model of generalized electrical machine, which allows to simplify the problem without considerable loss of the solution accuracy. For the parameters of the windings of a generalized electrical machine, the article presents the dependences of losses in the winding bars, coefficients of stray losses (Field factors) and slot leakage reactances on the dimensions of the strands and geometric dimensions of the slots. An analysis of the impact of parametric variations on the efficiency and dynamic characteristics of the machine is carried out. A comparison of the obtained results provides prerequisites for searching for the optimal dimensions of slot geometry.