Effect of capacitive auxiliary winding on a three- phase induction motor performance behaviour

Abstract: This paper investigates the effect of a capacitive three-phase auxiliary winding on the target variables of a threephase squirrel cage induction motor (SCIM). The three-phase auxiliary winding is only magnetically coupled to the stator main winding. The three-phase SCIM is modelled using 2D Finite Element Method (FEM). The flux density distribution is numerically computed through the magnetostactic solver, and the other target variables of interst such as the efficiency, power factor and torque are obtained through ac magnetic-transient solver. A conventional 4 kW, 50-Hz, and 4-pole three-phase SCIM is modified to accommodate both main and auxiliary windings in the stator slots. The results obtained from Finite Element Analysis (FEA) are compared with results from experimental measurement. From both simulation and experimental results, it is noted that the capacitive auxiliary winding has not only enhanced the power factor, but it also has a significant impact on the efficiency, torque and other electromagnetic parameters of the three-phase SCIM

Optimal modelling of planar thermal converter device

Abstract: The root mean square (rms) measurement of alternating voltage of any waveform is frequently done by means of thermal transfer instruments. The principle of these thermal rms converters is to transfer the heating energy of resistive load to a temperature-sensing element. The dc voltage output of the sensor reflects the amount of electrical power (ac or dc) applied to the input. This paper is addressing the modelling of a thermal converter device in planar technology using finite element platform. The original approach of this study capitalizes on introduction of a resistive thermal sensing element of a planar type to provision the thermal-conversion response to the active power dissipated on the 3D stratified non-reactive heater structure. Through iterative multi-physics simulations, model properties and dimensions have been evaluated and optimized

Dynamic analysis of a novel synchronous reluctance motor with a sinusoidal anisotropic rotor

Abstract: This paper deals with the dynamic analysis of a Novel Synchronous Reluctance Motor (NSynRM) having a sinusoidal rotor shape in the axial direction, without changing the flux-barriers design variables. Due to the non-self-starting characteristic of a Synchronous Reluctance Motor (SynRM), the motor is started by means of an industrial drive of ACS880 type. The motor is a 4-pole, 5.5 kW with a base speed of 1500 rpm. The practical tests are performed at three different speeds in order to analyze the dynamic responses when there is a sudden change in mechanical load characteristics. The measured results of the NSynRM are compared with those of a Standard Synchronous Reluctance Motor (SSynRM)

Torque per ampere enhancement of a three-phase induction motor by means of a capacitive auxiliary winding

Abstract: This paper presents the use of a capacitive three-phase auxiliary winding to enhance the torque per ampere of a three-phase Squirrel Cage Induction Motor (SCIM) for electric traction, which generally requires high torque density, a high power factor and high efficiency. The three-phase auxiliary winding is only magnetically coupled to the stator’s main winding. A conventional 5.5-kW, 50-Hz, and 4-pole three-phase SCIM is modified to accommodate main and auxiliary windings in the stator slots. The practical results evidenced that on no-load the torque per ampere is ± 5 times higher with the presence of a capacitive auxiliary winding that utilizes 80 μF per phase

Characterization and modeling of an RMS-DC solid-state thermal converter

Abstract: The Root Mean Square (rms) measurements of alternating signal of any waveform are frequently done by means of thermal transfer instruments. The principle of these thermal transfer instruments is to transfer the heating energy of resistive load to a temperature-sensing element. The DC output of the sensor reflects the amount of electrical power (ac or dc) applied to the input. The paper addresses the characterization and modelling of an RMS-DC thermal converter of a solid state technology type at various frequencies. The theoretical and simulation analysis is carried out to outline the factors influencing the transfer characteristics of the converter device in the dc and ac input regimes

Fault-tolerance of five-phase induction machines with mixed stator winding layouts : torque ripple analysis

Abstract The mixed winding layouts proposed in this paper are obtained by combining double and triple layer (DTL) windings in stator slots. Previous work has touched upon on the ability of three-and five-phase induction machines (IMs) with mixed winding layouts to produce torque with less ripple contents. However, their advantage when operating under open-circuited faults is yet to be comprehensively reported. This paper presents the fault-tolerant ability of Fivephase Induction Machines (FPIMs) with mixed winding layouts to produce torque with less ripple contents. The windings are designed as 2-pole and chorded with one slot, thereafter referred to as “DTL-14/15” and when chorded with two slots, thereafter referred to as “DTL-13/15. The magnetic conditions in the FPIMs are analyzed using Finite Element Method (FEM). The results evidenced that the FPIMs with the proposed DTL-14/15 and DTL-13/15 chorded coils reduced the torque ripple by a margin of about 60 % while operating with open-circuited faults respect to FPIMs with conventional double layer (DL) winding of the same coil span and operating under the same conditions. The results also prove that there is a great correlation between FEM (simulation) and experimental results

Performance analysis of a three-phase induction motor with capacitance injection

Abstract: In this paper a static switched capacitor with an auxiliary three-phase stator winding, which is only magnetically coupled to the stator main winding, is explored for improving the starting and operating power factor of a three-phase induction motor. The scheme improves the power factor of the motor without compromising significantly on other performances. Important advantages of the scheme include preventing harmonics in the line current, and eliminating regeneration possibility as well as preventing high inrush currents at starting

Diagnostic methods of frequency response analysis for power transformer winding a review

Abstract: Monitoring and diagnosis of power transformers in power systems have been investigated and discussed for the past decades. Earlier detect power transformer winding failures is recommended for both manufacturing process and also for power system operators. One of the most powerful and accurate tool for sufficient winding deformation detection is considered Frequency Response Analysis (FRA) among other diagnostic methods. In this paper a review of diagnostic methods of FRA for power transformer winding are presented. Different methods of transformer winding diagnosis, with their benefits and drawbacks where investigated. Moreover, possible windings failures, diagnostic methods of FRA in Off-line and On-line power transformers, detailed advantages and disadvantages of two major types of FRA are presented. The paper was able to show that some uncertainties have not been eliminated completely

An approach to quantify the technical impact of power quality in medium voltage distribution systems

Abstract: This paper provides a useful guidance in the interpretation and analyses of the technical impact of power factor correction in a power system. It is intended to raise awareness in order to achieve correct measurements, calculations and the key dynamics of the power system when quantifying the impact of power quality (PQ) in a non-linear power system. This paper is therefore targeting the power producing utilities, municipalities and the bulk end users of electricity

A study of improving the power factor of a three-phase induction motor using a static switched capacitor

Abstract: In this paper a static switched capacitor with an auxiliary three-phase stator winding, which is only magnetically coupled to the stator main winding, is explored for improving the starting and operating power factor of a three-phase induction motor. The scheme improves the power factor of the motor without compromising significantly on other performances. Important advantages of the scheme include preventing harmonics in the line current, and eliminating regeneration possibility as well as preventing high inrush currents at starting