Single Cage Induction Motor Research Articles

Dış Kafesinde Kırık Bar Arızası Olan Çift Kafesli Asenkron Motorun Performans Analizi

Induction motors are one of the most commonly used motor in the industry. For this reason, a fault (electrical or mechanical) inside or outside of the motor can cause the motor to go out of power and even cause the production losses inside the factory. Although there are many studies on single-cage induction motor failures in the literature, double cage motor failures are not a frequent subject of study. Therefore, in this study, it was investigated how the outer cage slot faults in a double cage induction motor affect the motor performance. Analyses were performed using Finite Element Method (FEM). 1, 2, 3 and 4 outer cage broken bars in the rotor slot were investigated. Rotor currents, magnetic vector potential values, magnetic flux distributions, current densities, radial forces and torque-speed graphs of the motor models were obtained and compared for both healthy and failure motors. The results show that as the number of broken bar in the rotor increased, a significant reduction was observed in all three torque (starting, maximum and nominal) values. It has been observed that the starting torque decreased by 13.77% for the 4 broken outer cage rotor bars motor according to the healthy motor.

A Simple Method to Determine Double-Cage Rotor Equivalent Circuit Parameters of Induction Motors From No-Load and Locked-Rotor Tests

This paper presents a simple method to determine double-cage rotor equivalent circuit parameters of induction motors (IMs). A new formula to calculate the double-cage rotor equivalent circuit parameters is proposed. The formula is sufficiently simple to be calculated by a calculator but can determine the parameters of outer- and inner-cage conductors. The proposed method takes the magnetic saturation effect of a closed-slot rotor into account and applies to not only double-cage but also single-cage IMs. All equivalent circuit parameters can be determined using only classical no-load and locked-rotor tests. Thus, the proposed method is suitable to be used as a standardized testing method for IMs. The validity of the proposed method is demonstrated by experimental results on four 5.5 kW-200 V-4 P-22 A-50 Hz IMs: double- and single-cage IMs with semi-closed- and closed-slot rotors.

Analytical determination of speed-torque and speed-current curves of single-cage induction motor under supply voltage and frequency variations

PurposeAn important characteristic of most induction motors is speed- or slip-torque curve. A simplified Kloss formula is widely used for describing speed-torque characteristic because it is fairly simple. Only two parameters related to break-down torque and break-down slip are regarded as input parameters. Because this simplified formula ignores an unknown parameter that is a ratio between Thevenin’s and rotor resistances, an accurate torque curve characteristic may not be fully obtained over an entire speed range. Moreover, the conventional Kloss formula does not offer a speed-torque curve calculation when motor’s supply voltages and frequencies are deviated from rated values. Hence, the purpose of this paper is to present an extension of Kloss formula, which allows a more precise estimation of speed-torque and speed-current curves of single-cage three-phase induction motors over a wide range of speeds at different motor’s operating voltages, frequencies and rotor-circuit resistances.Design/methodology/approachThe analytical approach is mainly used for determining all key parameters in the Kloss formula using a known set of data such as rated torque, starting torque, break-down torque and rated speed, in which they can be obtained from motor’s manufacturer.FindingsThe speed-torque and speed-current curves taken from laboratory measurements are compared with those from the calculations. Good agreements between them are fully observed.Originality/valueThis analytical approach is useful in providing an accurate speed-torque and speed-current curves required for most steady-state analysis.

An Induction Motor Speed Measurement Method Based on Current Harmonic Analysis With the Chirp-Z Transform

This paper presents a new method to measure motor speed by means of frequency estimation of rotor slot spectral components in the supply current of squirrel single-cage induction motors. The novelty of the method consists in the harmonic analysis of the supply current by means of the chirp-Z transform (CZT). The advantages are improved accuracy due to better spectral resolution and resolvability. Moreover, a shorter observation window is required, thus reducing errors related to nonstationary current signals. The experimental results are presented to validate the proposed method and to make a comparison with a similar method based on the fast Fourier transform (FFT).

Controller design using, μ-synthesis for static VAR compensator to enhance the voltage profile for remote induction motor loads

This paper deals with the design and implementation of a robust controller for the static VAR compensator (SVC) in remote industrial power system, to enhance the voltage profile for three phase single cage induction motor (SCIM) loads. The controller design is based on μ -synthesis method to deal with uncertainties arising in industrial network modeling. The performance of the controller has been evaluated extensively by non-linear time domain simulation. It is concluded that the robust controller enhances the voltage profile for SCIM loads compared with conventional SVC type (CSVC), which consist of voltage and current feedback loops.

Subsynchronous resonance of deep-bar induction motors

This paper presents the results of an investigation into the subsynchronous resonance (SSR) instability of deep-bar induction motors when supplied through series capacitor compensated feeders. As in a companion study published by the same authors on single-cage induction motors, useful physical insight into SSR instability is obtained from a simple equivalent circuit analysis and the discrete Fourier transforms (DFTs) of some of the transient waveforms. The main contribution of this paper is to show that, provided the stator resistance is below some minimum value, an unstable region will exist between an upper and lower resonant speed, as in the case of a single-cage motor.

Subsynchronous resonance of single-cage induction motors

This paper presents the results of an investigation into the subsynchronous resonance (SSR) instability of a single-cage induction motor supplied by a series capacitor compensated feeder. A great deal of insight into the mechanism of subsynchronous resonance instability is obtained from a simple equivalent circuit analysis and the discrete Fourier transforms (DFTs) of some of the transient waveforms.