Phase Squirrel Cage Induction Motor Research Articles

Manual Performance Analysis of a 2.2kw Refurbished ThreePhase Induction Motor

A refurbished 2.2kW 3-phase squirrel-cage induction motor was subjected to a steady-state performance analysis. It was earlier refurbished to reflect a prevailing local maximum 3-phase voltage level of 380Vac, as against the manufacturer's name-plate nominal voltage of 415Vac. The aim was to obtain from the motor at 380Vac satisfactory values of the operational quantities as obtainable at the original voltage level of 415Vac. To this end the method of open-circuit/short-circuit laboratory tests was adopted, the d.c. resistance test notwithstanding. The experimental calculations from these led to the determination of the machine equivalent circuit parameters by means of which the motor operational quantities and the performance curves for analytical purposes were obtained. MATLAB was used to generate the performance curves via the appropriate mathematical models. The analysis showed the motor as exhibiting satisfactory full-load values of torque, speed, output power, slip and power factor, although at the expense of full-load efficiency and starting properties.

Diagnosis of Stator Winding Short Circuit Fault in Three Phase Squirrel Cage Induction Machine

The objective of this paper is stator winding fault detection in three phase squirrel cage induction motor using Motor Current Signature Analysis (MCSA). A prototype model of the motor has been designed to study the stator winding faults through simulation and experimentation. Simulation has been carried out using MagNet 6.11.2. The simulated stator winding faults are inter-turn, phase-to-phase, open turn in a phase. The current signatures of simulation and hardware has been compared.

A new diagnosis of broken rotor bar fault extent in three phase squirrel cage induction motor

This paper proposes a new induction motor broken bar fault extent diagnostic approach under varying load conditions based on wavelet coefficients of stator current in a specific frequency band. In this paper, winding function approach (WFA) is used to develop a mathematical model to provide indication references for parameters under different load levels and different fault cases. It is shown that rise of number of broken bars and load levels increases amplitude of the particular side band components of the stator currents in faulty case. Stator current, rotor speed and torque are used to demonstrate the relationship between these parameters and broken rotor bar severity. An induction motor with 1, 2 and 3 broken bars and the motor with 3 broken bars in experiment at no-load, 50% and 100% load are investigated. A novel criterion is then developed to assess rotor fault severity based on the stator current and the rotor speed. Simulations and experimental results confirm the validity of the proposed approach.

A Novel Scheme for Reduction of Torque Ripple in Direct Torque Control of Three Phase Squirrel Cage Induction Motor Using Seven Level Neutral Point Clamped Inverter

Direct torque control of a 3 phase squirrel cage Induction motor though offers a good dynamic response and is free from dynamic coordinate transformation has a major disadvantage of producing rippled torque which degrades the performance of entire drive system. A scheme is proposed in this study which employs seven levels Neutral point clamped inverter which helps in alleviating the torque disturbances. The control scheme for the proposed method is described in this study and the simulation results are reported to demonstrate its effectiveness.

Magnet Software Based Fault Analysis of Induction Motor Using Finite Element Analysis

Induction motor is one of the most commonly preferred motors used in the industry due to its long life & rugged construction. Faults occurring in an induction motor can significantly affect the performance of the motor and the drive which is running it. This project aims to study & analyze the faults which can occur internally in an induction motor .To implement fault analysis first the machine is modeled using MAGNET software. The motor is studied under healthy conditions. Subsequently faults are introduced & fault analysis is carried out. In the model of induction rotor bars are broken and the study is mostly based on magnetic field analysis of the motor under healthy conditions & under faulty conditions. The variation of starting torque with respect to increasing number of broken rotor bars is studied and a graph was plotted to show the variation. The stator winding currents produce a magnetic field that rotates in a counterclockwise direction. The changing magnetic field of the stator induces electromotive force in the rotor cage winding. The induced emf causes current to flow and magneto motive force in the rotor windings. In turn the rotor mmfs produce a magnetic flux pattern which also rotates in the air gap at the same speed as the stator winding field. Induction motors are the most commonly used prime movers in industrial applications. They are best suited for constant speed applications. Speed control can also be done with the help of power converter circuits. The 3-phase squirrel cage induction motor is the workforce of the industry as it is rugged & reliable. The interaction between the primary field and secondary currents produces torque from zero rotor speed onwards. The rotor speed at which the rotor currents are zero is called ideal no-load or synchronous speed. The rotor windings may be multiphase (wound motors) or made of bars short-circuited by end rings (cage rotors). All primary and secondary windings are placed in the uniform slots stamped into thin silicon steel sheets called laminations. The induction machine has a rather uniform air gap of 0.2 to 3mm.The secondary windings may be short circuited or connected to an external impedance or to a power source of variable voltage and frequency. Induction motors are the most commonly used prime movers in industrial applications. They are best suited for constant speed applications. Speed control can also be done with the help of power converter circuits. The 3-phase squirrel cage induction motor is the workforce of the industry as it is rugged & reliable. Electrical related faults are frequently occurring faults in three-phase induction machine which will produce more heat on both stator and rotor winding. This leads to the reduction the life time of induction machine. Stator winding fault in Induction Motors can be detected using Unknown Input Observer (UIO) & Extended Kalman Filter methods. They are used for speed estimation and fault detection methods respectively(1).Using analysis of permeance and MMF harmonics, frequency of air gap flux density harmonics which occur due to irregularities are calculated. It helps in detecting faulty ball bearing conditions (2). A procedure for electromagnetic design of three phase Induction Motor is discussed. This procedure is based on self-consistent equations. The electrical and magnetic properties are imposed by the user but the geometric dimensions are automatically calculated (3).The choice between Copper rotor bars and fabricated Aluminum rotor bars is discussed and debated. The fundamentals of rotor construction and basic information on how the Induction Motor works are discussed (10). The new IEC standard which defines the stator winding insulation requirement when the Induction Motor operates with Adjustable frequency drives (AFDs) is discussed. The

SIMULINK Based Model for Determination of Different Design Parameters of a Three Phase Delta Connected Squirrel Cage Induction Motor

Electrical Machine Design is a renown discipline of electrical engineering, which can be termed as the physical implementation of theoretical knowledge .A machine is designed considering different aspects like- quality and availability of materials, availability of suitable mechanism and skilled labor, cost, durability etc. In this paper, a computer based model (using SIMULINK) is furnished for obtaining the suitable dimensions of a three phase squirrel cage induction motor. The main objective of the work is to determine the dimensions of various parts and components of the motor, specify suitable materials for design and obtain the output parameters. Now-a-days, induction motors have become the workhorse of the industrial sector due to their easy means of construction and maintenance. Therefore, the performance of the machine needs to be specified using computer aided programs. In this paper, the input parameters of the induction motor is so chosen that it will

Analysis of Efficiency, Thermal Withstanding Capacity and Electromagnetic Interference of Three Phase Squirrel Cage Induction Motor Coated with SiO2 & TiO2 NanoComposite Filled Enamel

Three phase induction motors consume 60% of industrial electricity. Just 1% increase in efficiency of all the motors in India will save 500 MW powers which needs the initial generation cost of 2000 crores. Actions were taken to use the enamel filled with SiO2 and TiO2 nanocomposite as the coating for the induction motor to improve its efficiency. The efficiency of the induction motor was increased by 5% by adding nanocomposites of SiO2 and TiO2 (1:3) to the enamel used as the coating for the windings of the three phase squirrel cage induction motor. Heat run test was performed on electrical machines to determine the total loss of energy dissipated as heat. The addition of nanocomposites to the enamel has increased the temperature withstanding capacity of the induction motor. The values of electromagnetic inference produced by normal induction motor and nano coated induction motor was also measured and analyzed. There was a reduction of 15 to 60% in the values of the electromagnetic interference produced by the normal induction motor when compared to that of nanocomposite filled enamel coated induction motor at various distances. This method can be used as one of the method to reduce the electromagnetic interference by the induction motors.

Performance Analysis of Three Phase Squirrel Cage Induction Motor with Deep Rotor Bars in Transient Behavior

The rotor parameters, the resistance and the leakage inductance, vary with the currents frequency of rotor bars due to skin effect, and for small frequencies can be negligible (under 10 15 Hz); but for higher frequencies this variation of the parameters cannot be negligible. In this paper, for higher frequencies some analytic expressions are proposed, that result from the skin effect theory, for the rotor resistance and for the leakage inductance. The simulations were done by SYMNAP - SYmbolic Modified Nodal Analysis Program, a program that can determine, in a full-symbolic form the voltages and the currents for the equivalent scheme for one phase of the asynchronous motor. Symbolic expressions for the characteristics quantities of the general regime of the induction motor allow graphic representation for different parameters. These analytic expressions allows a more accurate analysis of asynchronous motor performance for different drive systems. To simulate the dynamic (transient) behavior of the induction motor, Park-Blondel equations have been used; these equations have a nonlinear form due to both their structure and frequency variation of the rotor parameters. The integration of these equations is performed with the help of the integration routines for ordinary differential equations in Matlab programming environment. It was found that the nominal values of the quantities that characterize the induction motor operation, obtained by simulation, practically coincide with the values from the catalogue.

Fuzzy Logic Control of an Induction Motor Compared with PI Contro

In this work, a model of fuzzy logic controller (FLC) was designed to regulate the speed of a 3-phase squirrel cage induction motor. The model was created in Simulink and simulated in MATLAB environment. The motor was tested at speeds of 120 rad/sec and 140 rad/sec under no-load condition and simulation results were obtained. The speed of the motor was tested under the same condition but using Proportional + Integral (PI) controller. The results show that the PI controller could be replaced with the fuzzy logic controller due to the advantages of relatively short settling time and small overshoot. The settling time for the speed and torque for the FLC were 0.7s and 1.0s, while that of the PI controller were 1.0s and 2.1s respectively. Similarly, the overshoot was higher in the simulation results obtained for the torque and speed curves when the motor was tested with the PI controller than with the FLC. Finally, for the motor considered, it was found that the PI controller introduces nonminimum phase behavior in the system while the FLC does not. Keywords: Induction motor, Simulink model, fuzzy logic control, proportional + integral control, nonminimum phase.

NEW DESIGN CORRELATIONS FOR SINGLE PHASE INDUCTION MOTOR SQUIRREL CAGE

In this research, new easy and fast correlations derived from practical data for the design single phase squirrel cage induction motor that enable us to select its main dimensions with depending on the required power, see fig.(1), also making empirical correlations connecting between the motor power and its dimensions for multi-ranges. Data of these correlations were got practically and formulated mathematically by using Mathematical Matrix Model is called Pseudo Inverse.

Precise derating of three phase induction motors with unbalanced voltages

Performance analysis of three phase induction motors under supply voltage unbalance conditions is normally conducted using the well-known symmetrical components analysis. In this analysis, the voltage unbalance level at the terminals of the machine is assessed by means of the NEMA or IEC definitions. Both definitions lead to a relatively large error in predicting the performance of a machine. A method has recently been proposed in which, in addition to the voltage unbalance factor (VUF), the phase angle has been taken into account in the analysis. This means that the voltage unbalance factor is regarded as a complex value. This paper shows that although the use of the complex VUF reduces the computational error considerably, it is still high. This is proven by evaluating the derating factor of a three phase induction motor. A method is introduced to determine the derating factor precisely using the complex unbalance factor for an induction motor operating under any unbalanced supply condition. A practical case for derating of a typical three phase squirrel cage induction motor supplied by an unbalanced voltage is studied in the paper.

A Computationally Efficient Winding Function Method for Calculation of Inductances in an Asymmetric Induction Motor

Winding function theory has been successfully applied for the calculation of magnetizing inductances of asynchronous and synchronous rotating machines for steady-state and transient analysis. The computational burden in such simulations is heavy because of the calculation of a large number of inductances of the stator and rotor circuit coils, at every time step, each of which requires evaluation of definite integrals of the products of winding functions, their distributions and inverse air gap functions around the rotor periphery. This article proposes a modified discrete space model of continuous space winding function of a squirrel cage induction motor. The discrete model uses the air gap functions directly and consequently eliminates inverse air gap functions and their approximations. Further, it uses simple and direct formulae for the calculation of motor inductances, which results in considerable reduction in the computational complexity and execution time while preserving the accuracy of computation. Discrete winding functions are suitable for the simulation of gradual changes in asymmetrical faults such as eccentricity, rotor bar faults and end ring faults in a three phase squirrel cage induction motor. Simulation results show the comparative assessment of computational complexity, accuracy and execution time required for the calculation of the stator and rotor inductance values of an asymmetrical induction motor.

Facilitation for Load Based Energy Savings in Three–phase Squirrel Cage Induction Motors

ABSTRACT Electrical motors use a significant amount of electricity. Increasing the motor efficiency has an impact on the reduction of energy consumption. There have been efforts to increase motor efficiency over the past decade that have led to the development of premium efficiency motors. The motor efficiency decreases under conditions of low load factor. It is important to match the motor power with that required for the application that it serves, as this will increase operational efficiency. Accurate load determination methods, such as input power measurement, are time-consuming and have safety hazards that need to be mitigated. The development of a method that aids the sizing of electric motors that is simple to use, economical, safe, and accurate, is important. This article reports on data collected during fifteen energy assessments conducted at a variety of manufacturing facilities using the motor load monitoring method as well as the stroboscope method. An analysis of the data was conducted to det...

06/01762 Influence of unbalanced voltage supply on efficiency of three phase squirrel cage induction motor and economic analysis: Faiz, J. et al. Energy Conversion and Management, 2006, 47, (3), 289–302

06/01762 Influence of unbalanced voltage supply on efficiency of three phase squirrel cage induction motor and economic analysis: Faiz, J. et al. Energy Conversion and Management, 2006, 47, (3), 289–302

Influence of unbalanced voltage supply on efficiency of three phase squirrel cage induction motor and economic analysis

Abstract The negative effect of unbalanced voltage upon the losses and efficiency of a three phase squirrel cage induction motor is investigated. The financial losses caused by unbalanced voltage of the power supply are determined using an analytical–statistical method. The analytical method is verified by experimental test.

Comparison of standards for determining efficiency of three phase induction motors

The paper describes a set of experiments and discusses their results for determining the efficiency of low voltage, three phase squirrel cage induction motors. The measured efficiency of an induction motor directly connected to the grid, strongly depends on the method used to evaluate the results and the standard according to which the measurements are performed. Different standards as IEEE 112 and IEC 32 are mentioned and their similarities and differences are discussed. The main discrepancies between the various standards is the way in which the values for the stray load losses are obtained at different load levels. A short description of the measurement setup is given and measurement results for motors of several manufacturers accounting for different standards are proposed. The results clearly demonstrate the necessity to handle the efficiency data given by the manufacturer with a lot of care.

Waveform of Magnetic Flux in Squirrel Cage Induction Motor Driven by PWM Inverter

The waveforms of the magnetic flux and induced voltage in the stator core, stator teeth, and rotor core of a 3-phase squirrel cage induction motor driven by a V/f = const PWM inverter power supply were measured and compared with those of the motor driven by a sinusoidal power supply, to estimate the magnetic losses. The waveforms of the induced voltage in each driving condition were similar to those of the primary winding voltage, while those of the magnetic flux in both conditions were approximately sinusoidal. The induced voltage waveform of the stator teeth contained higher harmonics, owing to the rotor slots and the power supply waveform, and differed depending on the positions of the teeth only in the case of the inverter supply. It was found that the voltage waveform for some teeth spaced at constant intervals was sinusoidal owing to self-cancellation of the harmonics. The flux in the rotor core was a sinusoidal waveform of the slip frequency multiplied by the pole pair number, which contained higher harmonics due to the stator slots, the power supply waveform, the primary voltage imbalance, and the air-gap nonuniformity between the stator teeth and the rotor.

Magnetic losses of electrical iron sheet in squirrel-cage induction motor driven by PWM inverter

In order to understand the magnetic behavior of electrical iron sheets assembled into an actual motor core driven by a PWM inverter, we have observed induced voltages and magnetic inductions in the stator core, the stator teeth, and the rotor core of a 3-phase squirrel-cage induction motor driven by both a sinusoidal power supply and a V/f=const PWM inverter power supply, and estimated the magnetic losses in the motor. Though the waveforms of the magnetic flux at the stator core in both driving conditions were approximately sinusoidal, the induced voltage waveforms in each driving condition were similar to the source voltage waveforms. The induced voltage waveform of the stator teeth contains higher harmonics, due to the rotor slots and the power supply waveform, and differs depending on the positions of the teeth only in the case of the inverter supply. The magnetic flux in the rotor core showed a sinusoidal waveform with the slip frequency multiplied by pole pair number, which contained higher harmonics due to the stator slots, the power supply waveform, the primary voltage imbalance, and the nonuniform air-gap between the stator teeth and the rotor core. In spite of the complex distribution of the magnetic induction in the motor core for PWM inverter drive, the magnetic losses of the motor are estimated to be proportional to the running frequency of the inverter and increase from those at the sine drive by a certain rate corresponding to the eddy current losses.

Analysis of Higher Harmonic Components in Magnetic Fields on Three Phase Squirrel-Cage Induction Motors Considering Higher Harmonics in the Secondary Current.

Reduction of machine size increases the number of harmonic components which appear in the magnetic fields on induction motors. For practical design, it is necessary to estimate these harmonic components. This paper describes a method to analyze harmonic fields on induction motors, considering higher harmonics in the secondary current. The method consists of two parts. One is the magnetic field calculating part done by a 2D-finite element method considering rotor rotation, and the other is the harmonics analyzing part done by considering space and time harmonic components using the former results.Dependence of periodicity in the magnetic fields on driving conditions is discussed. Then the relationship between the analysis period, the method of mesh division, and the periodicity is clarified for calculating magnetic fields. From the comparison between calculated and experimental results, the proposed method is shown to be appropriate and useful for quantitative estimation of harmonic components on induction motors.

Optimum design of a three phase squirrel-cage induction motor based on efficiency maximization

Efficiency maximization of a three phase squirrel-cage induction motor with constraints imposed upon the performance characteristics of the motor is carried out. Initially a computer program, based upon the numerical and analytical design procedures, has been developed for the design of a three phase squirrel-cage induction motor and its calculated performance has been validated against the performance of the squirrel-cage motor of standard commercial design. The output of this program is the input of the optimization program. A non-linear optimization routine for the motor design is used and this optimized design is compared with those obtained using other optimization procedures and a more complicated optimization procedure. The pattern search method of Hooke-Jeeves is used successfully, by direct imposition of constraints, for optimum design of a 5 h.p. motor. The results of the optimization consisting of variations of the performance conditions and relative variations of these characteristics, are then compared with the results of the optimization based upon the Han-Powell procedure, simple and modified Hooke-Jeeves methods. This comparison indicates that, in spite of different optimization variables and routines used, the relative variations of the performance characteristics are similar.