External Search Coil as a Means of Measuring Rotor Speed of an Induction Motor

2009-07-03
The study in this paper investigates whether the air gap harmonics can be identified by using an external search coil placed on the frame of an induction motor. For this purpose the study focuses on the prediction of rotor speed of an induction motor from external search coil emf, using spectral analysis techniques. In the first stage of the study the type of search coil which maximizes the induced emf is sought, also the position of the coil on the induced emf is investigated. Several motors are tested with a sinusoidal supply as well as a PWM inverter power supply and the search coil voltage is sampled. FFT analysis of the recorded data is performed in Matlab environment. An algorithm is developed for identifying the rotor speed using the FFT analysis results. It is shown that the developed algorithm is capable of predicting the motor speed under various load conditions and motor speeds. The speed estimation accuracy of this approach is also discussed. In short, this paper illustrates that the induced emf in an external search coil contains information on air gap harmonics, and these harmonics can be identified even when the motors are supplied with a PWM inverter.

Suggestions

Ultra-fast charge exchange spectroscopy for turbulent ion temperature fluctuation measurements on the DIII-D tokamak (invited)
Uzun Kaymak, İlker Ümit; McKee, G. R. (2012-10-01)
A novel two-channel, high throughput, high efficiency spectrometer system has been developed to measure impurity ion temperature and toroidal velocity fluctuations associated with long-wavelength turbulence and other plasma instabilities. The spectrometer observes the emission of the n = 8-7 hydrogenic transition of C+5 ions (lambda(air) = 529.06 nm) resulting from charge exchange reactions between deuterium heating beams and intrinsic carbon. Novel features include a large, prism-coupled high-dispersion, v...
Development of high performance uncooled infrared detector materials
Kebapçı, Başak; Akın, Tayfun; Turan, Raşit; Department of Micro and Nanotechnology (2011)
This thesis reports both the optimizations of the vanadium oxide (VOx) thin film as an active infrared detector material by the magnetron sputtering deposition method and its use during fabrication of proper resistors for the microbolometers. Vanadium oxide is a preferred material for microbolometers, as it provides high TCR value, low noise, and reasonable resistance, and a number of high-tech companies have used this material to obtain state-of-the-art microbolometer arrays. This material is first used in...
Transient response of an infinite elastic medium containing a spherical cavity subjected to torsion
Zakout, U; Akkas, Z; Tupholme, GE (2000-06-01)
An exact closed-form solution is obtained for the transient response of an infinite isotropic elastic medium containing a spherical cavity subjected to torsional surface loading using the residual variable method. The main advantage of the present approach is that it eliminates the computational problems arising in the existing methods which are primarily based on Fourier or Laplace transformation techniques. Extensive numerical results for the circumferential displacements and shear stresses at various loc...
Bilateral CMUT Cells and Arrays: Equivalent Circuits, Diffraction Constants, and Substrate Impedance
KÖYMEN, Hayrettin; ATALAR, ABDULLAH; Tasdelen, A. Sinan (Institute of Electrical and Electronics Engineers (IEEE), 2017-02-01)
We introduce the large-signal and small-signal equivalent circuit models for a capacitive micromachined ultrasonic transducer (CMUT) cell, which has radiating plates on both sides. We present the diffraction coefficient of baffled and unbaffled CMUT cells. We show that the substrate can be modeled as a very thick radiating plate on one side, which can be readily incorporated in the introduced model. In the limiting case, the reactance of this backing impedance is entirely compliant for substrate materials w...
Diffusion Equation-Based Finite Element Modeling of a Monumental Worship Space
Gul, Zuhre Su; Xiang, Ning; Çalışkan, Mehmet (World Scientific Pub Co Pte Lt, 2017-12-01)
In this work, a diffusion equation model (DEM) is applied to a room acoustics case for in-depth sound field analysis. Background of the theory, the governing and boundary equations specifically applicable to this study are presented. A three-dimensional geometric model of a monumental worship space is composed. The DEM is solved over this model in a finite element framework to obtain sound energy densities. The sound field within the monument is numerically assessed; spatial sound energy distributions and f...
Citation Formats
H. G. Özlü Ertan and O. Keysan, “External Search Coil as a Means of Measuring Rotor Speed of an Induction Motor,” 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/55590.