A control system for a three-phase-single- phase induction electric drive with a controlled phase-shifting module is developed and studied to result in a symmetric regime under stochastic load variations.
A reverse operation feasibility in three-phase asynchronous motors with the stator hexaphase windings is proved. In the reverse mode, the hexaphase windings are shown to keep all their declared advantages.
A passive magnetic vibration isolator (a magnetic spring) with cylindrical magnets is considered. A mathematical model is developed to calculate magnetic spring magnetic field and force. Numerical calculation of the vibration isolator magnetic field via a 3-D finite element method is performed. Experimental results presented prove adequacy of the computational data.
An equivalent thermal circuit is developed to form the basis of a system of heat-balance equations for a frequency-controlled induction motor. With the system of equations, temperatures of АИР 90В2 induction motor stator and rotor windings and cores are calculated and experimentally confirmed. The load dependence of the machine most heated units temperature at different forms of the supply voltage is revealed.
Analytical expressions for magnetic force gradient computation are given. FEM simulation of the matrix core in the working gap of a magnetic system is conducted. The magnetic force distribution is presented as a relative ratio. A force balance equation taking into account the magnetic force pattern is derived.
A 2-pole winding development technique is introduced for asynchronous machines with the number of parallel branches in phases increased in 1.5 and 2 times as compared with the number of poles. The technique is confirmed by results of pilot studies.
A feedforward neural network based diagnostic model of oil-impregnated paper insulation of a current transformer has been developed. Its experimental validation as compared with a regression model has been performed.
Peculiarities of heat and vibration parameters determination are substantiated for electric machines with extended failure interval under conditions of defects in the main structural units and elements. The necessity of their application to improving the existing research methods and reliability models and developing new ones is grounded.
A methodology of an asynchronous motor mathematical model synthesis is described. Experiments are suggested to be conducted in the following sequence. Geometrical models are first built in AutoCAD, then imported to Comsol Multiphysics, and further processed in Matlab with computation of coefficients and dependences applied in the asynchronous motor mathematical model.
A critical assessment of the existing views on the world energy development prospects is an integral part of independent policy elaboration in this field for any state. Consideration of prospective power industry development options is a determinative factor in electric machine-building progress as a generation system production industry.
For spatial three-phase axial electromagnetic systems with circular and hexagonal cross-section configurations of twisted butt-end magnetic core rods, analytical dependences for optimal geometrical relations determination over the transformer minimum watt loss criterion are obtained, comparative analysis of the systems energy efficiency made.
Dependence of a single switching procedure cost upon the contact opening delay time and delay-time spread is derived for a low-voltage synchronous vacuum contactor. For different cost levels, boundaries of permissible values of delay-time and delay-time spread are specified.
An advanced way of induction heating of nonmagnetic billets is discussed and modeled. The billet rotates in a stationary magnetic field produced by unmoving high-parameter permanent magnets fixed on magnetic circuit of an appropriate shape. The mathematical model of the problem consisting of two coupled partial differential equations is solved numerically, in the monolithic formulation. Computations are carried out using our own code Agros2D based on a fully adaptive higher-order finite element method. The most important results are verified experimentally on our own laboratory device.
A temperature dependence identification technique is worked out for graphitization furnace center-punch specific electrical resistance through applying a special object-oriented functional basis and temperature dependences of its components specific electric resistance. High accuracy of 3D electromagnetic field simulation data processing during electrode graphitization is maintained.