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ABSTRACT: The advantages of higher-phase-order drives are reviewed, and
results of investigations of a five-pulse inverter-fed induction motor
are presented. Methods of improving the waveform of the motor phase
current in the five-phase drive are examined theoretically as well as
experimentally. A mathematical model based on complex symmetrical
components is developed for theoretical investigations, and a prototype
five-phase inverter-fed induction motor drive is fabricated to conduct
experimental studies. Theoretical and experimental results under various
operating modes are presented. The studies establish that the five-phase
drive operates satisfactorily when it is fed from a pulsewidth-modulated
inverter
IEEE Transactions on Power Electronics 05/1988; · 4.65 Impact Factor
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ABSTRACT: A computer program is developed for the optimisation of single-winding dual speed induction motors using the least p th approximation method combined with the Rosenbrock technique. The overall economy in designing the motors for minimum operating cost is brought out with examples. Optimisation results show that the performance values, as well as manufacturing cost, are essentially the same for a dual-speed motor of a given kW rating and pole combination designed for various duty cycles. The treatment of independent variables, and constraint specifications and the logic incorporated in the program are discussed
Electric Power Applications, IEE Proceedings B [see also IEE Proceedings-Electric Power Applications] 02/1988; 135(1):33-38.
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ABSTRACT: Pole-changing windings using star/star-delta switching for 4:1 and 7:1 pole combinations have been developed. For arriving at these designs, a universal computer program has been developed, for a straightaway application for any pole combination (close-ratio or wide-ratio). The program has the merit that it can be applied by anyone without an elaborate study of the too many techniques presented in the literature for the design of pole-changing windings during the last two and half decades. Test results on laboratory size machines wound with the proposed 8/2 and 14/2 pole-changing windings are found superior to the earlier designs in all respects. The proposed windings are fully upto the normal industrial standards, and are suitable for crane, hoist and other similar wide-speed ratio industrial applications.
IEEE Transactions on Energy Conversion 01/1987; · 2.27 Impact Factor
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ABSTRACT: Pole-changing single-winding schemes are applied to self-excited induction generators for the first time and shown to be suitable for wind-driven applications with wide variations in the driving speed. An attempt has also been made to present an analysis of self-excited induction generators by a new approach which is shown to be simple and elegant compared to the earlier methods. Results on a test machine wound with a 4/6-pole combination amply demonstrate the usefulness of pole-changing windings for induction generators. Experimental and predicted performances agree closely, validating the analysis proposed.
Electric Power Applications, IEE Proceedings B [see also IEE Proceedings-Electric Power Applications] 12/1986;
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ABSTRACT: A new pole-changing winding using star/star-delta switching is developed and is shown suitable for wide pole-ratio single-winding induction motors with pole combinations of the form (i) even/even and (ii) odd/odd pole pairs. Examples of 1:5 and 5:1 pole ratios are presented. Test results on laboratory-size machines for these pole ratios confirm the usefulness of the proposed schemes. The proposed arrangements are found to be superior to earlier designs in respect of either MMF/harmonic content or frame utilisation at both the pole settings. Change of speed is obtained using only six terminals and a control gear which is even simpler than the one used for any other pole-changing 3-phase winding.
Electric Power Applications, IEE Proceedings B [see also IEE Proceedings-Electric Power Applications] 04/1983;
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ABSTRACT: A detailed study of the asynchronous performance of slitted solid-rotor reluctance machines is presented when axial copper conductors are provided in the slits or slots, or both. Further, the influence of end terminations with and without conducting end rings on the asynchronous performance of the motor is also discussed. Theoretical investigations are based on three equivalent circuits presented for this purpose and are fully supported by extensive experimental results.
IEEE Transactions on Aerospace and Electronic Systems 04/1983; · 1.10 Impact Factor
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ABSTRACT: Analytical investigation based on limiting nonlinear theory presented here for the asychronous performance of a slitted solid iron rotor reluctance machine include the effect of rotor iron saturation. Characteristic curves depicting nondimensional expressions developed for the rotor impedance factor and the power factor enable a visualization of the effects of 1) ratio of depth of saliency to depth of penetration, 2) slit number and depth, and 3) effective resistivities and saturation flux densities of different regions of the rotor on rotor parameter variations. Further predicted values are compared with experimental values and conclusions are drawn.
IEEE Transactions on Aerospace and Electronic Systems 02/1983; · 1.10 Impact Factor
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Electric Machines and Power Systems 09/1982; 7(5):397-414.
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ABSTRACT: The asynchronous performance of a polyphase reluctance machine with rotor provided with axial slits is investigated for the first time on the basis of conductor boundary treated as a flux line. Theoretical and experimental investigations are presented for rotors with 1) many values of pole arc/pole pitch ratio, 2) varying slot depths, 3) slots on either pole faces or slot portions or both of them, and 4) with and without terminating end rings. Their comparison with predictions leads to interesting conclusions.
IEEE Transactions on Aerospace and Electronic Systems 02/1982; · 1.10 Impact Factor
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ABSTRACT: By using an approximate summation process it has been demonstrated that the optimum ratio of rotor to stator slot combination is 1 1/2 for a single-phase inductor alternator. An elegant and rigorous mathematical proof for this optimum ratio is presented here.
IEEE Transactions on Aerospace and Electronic Systems 04/1978; AES-14(2):386-388. · 1.10 Impact Factor
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ABSTRACT: The mathematical analysis of a single-phase inductor alternator presented here asserts that rotor slot restrictions apply only for alternators with conventional double winding. Schemes using single winding for both dc excitation and single-phase output are developed and their designs are discussed. It is demonstrated that the proposed schemes are superior in performance to conventional schemes. Test results on a number of laboratory size machines fully support the theoretical findings.
IEEE Transactions on Aerospace and Electronic Systems 12/1976; · 1.10 Impact Factor
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ABSTRACT: A computer program for the design of a dual-speed single-winding 3-phase induction motor is presented. A novel feature of the program is the treatment of different classes of pole ratios by a unified logic, enabling an exhaustive study of the effects of initial pole distribution, coil pitch and switching arrangement on performance at both speeds.
Electrical Engineers, Proceedings of the Institution of. 12/1976;
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ABSTRACT: Based on mathematical analysis, this paper points out that restrictions in stator/rotor slot combinations for optimum output of a conventional inductor alternator are not applicable for one with a single winding for both dc excitation and output. Design considerations for the latter are discussed, and it is demonstrated that its performance is superior to a conventional double-winding inductor alternator in all aspects. Test results on a number of experimental machines fully support the theory.
IEEE Transactions on Aerospace and Electronic Systems 10/1974; · 1.10 Impact Factor
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ABSTRACT: The performance of polyphase induction machine with hollow ferro-magnetic rotor is presented here for the first time on the basis of a definite value of the magnetising force existing on the inner surface of the rotor, this value increasing as wall thickness decreases.
IEEE Transactions on Power Apparatus and Systems 08/1972;
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ABSTRACT: Magnetic web of a hollow rotor induction machine leads to an improvement in performance. An analysis based on field theory attempted here brings out this aspect and also accounts satisfactorily for (i) Saturation, (ii) rotor wall thicknesses and (iii) end termination. Comparison with test results shows good agreement.
IEEE Transactions on Power Apparatus and Systems 08/1972;
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ABSTRACT: A low-speed polyphase motor is developed. The stator windings are designed, for simultaneously producing two different pole numbers in the air gap. The permeance distributed rotor interacts with one of the stator flelds and during the process generates the second one. The latter reacts with its stator counterpart, resulting in torque production.
IEEE Transactions on Power Apparatus and Systems 08/1972;
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ABSTRACT: The pole amplitude modulation method of obtaining economic and efficient two-speed operation from a normal single winding has been extended to two-phase motors. Extensive theoretical analysis supported by exhaustive experimental results covering numerous pole ratios forms a useful addition to the existing literature on armature windings.
IEEE Transactions on Power Apparatus and Systems 08/1970;
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ABSTRACT: The phase modulation method of induction motor speed changing with single-winding machines has been extended to two-phase machines. The paper presents theory and design methods and shows for the first time that phase modulated motors can be wound with standard coils of equal turns and pitch. The study also brings out a useful comparison of amplitude and phase modulation techniques. The work is supported by extensive experimental investigations covering numerous pole ratios.
IEEE Transactions on Power Apparatus and Systems 08/1970;
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ABSTRACT: A single-unit reluctance converter is discussed. The rotor used is of a double-permeance type, and a method of optimizing its shape for any frequency ratio is attempted. In tune with the present trend, single-winding arrangements are proposed for the stator. Further extension for simultaneous double-frequency conversion makes it all the more versatile. Apart from theory and design, experimental investigations on five laboratory-size machines establish the soundness of the schemes.
IEEE Transactions on Power Apparatus and Systems 06/1970;
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ABSTRACT: An analysis is developed for the starting performance of single-phase induction motors having asymmetrical windings not in quadrature. Based on Morrill's double-revolving field concept, the analysis leads to an equivalent circuit which accounts satisfactorily for all the space harmonics including those arising from irregular winding distribution. All the parameters for the equivalent circuit can be calculated from the design details.
IEEE Transactions on Power Apparatus and Systems 05/1970;
