Design and development of a disc-type tachogenerator in conjunction with the measurement of the torque/speed characteristics of an induction motor

Pao Yue-kong Library Electronic Theses Database

Design and development of a disc-type tachogenerator in conjunction with the measurement of the torque/speed characteristics of an induction motor

 

Author: Yau, Wai-tak
Title: Design and development of a disc-type tachogenerator in conjunction with the measurement of the torque/speed characteristics of an induction motor
Degree: M.Sc.
Year: 1996
Subject: Electric motors, Induction
Hong Kong Polytechnic University -- Dissertations
Department: Multi-disciplinary Studies
Pages: vii, 79 leaves : ill. (some col.) ; 30 cm
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b1231789
URI: http://theses.lib.polyu.edu.hk/handle/200/5003
Abstract: In Hong Kong, the torque/speed characteristic of large induction motor cannot be tested by a simple and economic method. This project outlines an effective method to estimate the torque/speed characteristic of an induction motor in a simple and economic way. This method can also be used in measuring torque/speed characteristic of large induction motor which is most popular work-horse in Hong Kong. Basically, the project is sub-divided into two parts. The first part is the main task of the project which deals with development of a disc-type tachogenerator that can be used to trace the torque/speed characteristic of an induction motor. Since this special designed disc-type machine is not available in the market now, it is anticipated that a mass production of the machine will be economical in measuring torque/speed characteristic of induction motor. The second part of the project is to develop a dedicated software program to decode the signals from a brushless synchro resolver which is expensive but is already available in the market. The program is able to measure and plot the torque/speed curve of induction motor using those captured signals. One of the objectives of this project is to compare the results from Parts A and B in terms of cost, efficiency and accuracy, etc. The detailed methodology of both parts are listed below: Part A: This is concerned with the design and manufacture of a disc-type machine that consists of a 3-phase 4-pole stator with a matching rotor. The rotor is fitted with four electromagnets fed with d.c. source via two slip-rings. When used in monitoring the torque/speed characteristics of an induction motor, the disc-type machine is mechanically coupled to the former. As the rotor of the disc-type machine rotates at the same speed of the induction motor being tested, the stator windings of the disc-type machine will induce a voltage which is proportional to common speed of the two machines. The speed dependent output of the machine is fed into an electronic circuit to produce a rippleless d.c. that is proportional to the speed of the induction motor. A suitable differentiator is to be developed to differentiate the speed signal. Since the output torque of the induction motor on no-load is proportional to the time differential of its shaft speed (i.e. T = J帢), the speed differential when obtained, is directly proportional to the output torque of the induction motor. By plotting the speed and the torque signal against each other, the torque/speed characteristics of the induction motor can be obtained. Part B: A brushless synchro resolver is bought from the market that provides a signal corresponding to the position the motor shaft. The output from the resolver is a frequency modulated signal which can also be processed to give an indication of the motor speed. A relatively complicated software is required to decode the signal from the resolver which is, incidentally, very expensive. The cost, efficiency and accuracy of the disc-type machine and the resolver in determining the output torque/speed characteristics of an unloaded induction motor are thoroughly studied in this project.

Files in this item

Files Size Format
b12317895.pdf 3.342Mb PDF
Copyright Undertaking
As a bona fide Library user, I declare that:
  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

     

Quick Search

Browse

More Information