# Electrical Machines I (Testing Of DC Machines)

 Course Code : ULZ0074 Author : uLektz University : General for All University Regulation : 2017 Categories : Electrical & Electronics Format : ePUB3 (DRM Protected) Type : eBook

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Description :Electrical Machines I (Testing Of DC Machines) of ULZ0074 covers the latest syllabus prescribed by General for All University for regulation 2017. Author: uLektz, Published by uLektz Learning Solutions Private Limited.

Note : No printed book. Only ebook. Access eBook using uLektz apps for Android, iOS and Windows Desktop PC.

##### Topics
###### UNIT I :PRINCIPLES OF ELECTROMECHANICAL ENERGY CONVERSION

1.1 Electromechanical Energy Conversion - Forces and Torque In Magnetic Field Systems - Energy Balance

1.2 Energy and Force in A Singly Excited Magnetic Field System - Determination of Magnetic Force - Co- Energy - Multi Excited Magnetic Field Systems

###### UNIT II:D.C. GENERATORS -I

2.1 D.C. Generators - Principle of Operation - Constructional Features

2.2 Armature Windings - Lap and Wave Windings - Simplex and Multiplex Windings - Use of Laminated Armature

2.3 E. M.F Equation - Numerical Problems - Parallel Paths-Armature Reaction

2.4 Cross Magnetizing and De-Magnetizing AT/Pole - Compensating Winding - Commutation - Reactance Voltage - Methods of Improving Commutation

###### UNIT III:D.C GENERATORS – II

3.1 Methods of Excitation - Separately Excited and Self Excited Generators - Build-Up of E.M.F

3.2 Critical Field Resistance and Critical Speed - Causes for Failure to Self Excite and Remedial Measures - Load Characteristics of Shunt - Series and Compound Generators

3.3 Parallel Operation of D.C Series Generators - Use of Equalizer Bar and Cross Connection of Field Windings - Load Sharing

###### UNIT IV:D.C. MOTORS

4.1 D.C Motors - Principle of Operation - Back E.M.F - Circuit Model - Torque Equation - Characteristics and Application of Shunt, Series and Compound Motors

4.2 Armature Reaction and Commutation - Speed Control of D.C. Motors: Armature Voltage and Field Flux Control Methods

4.3 Ward-Leonard System - Braking of D.C Motors - Permanent Magnet D.C Motor (PMDC)

4.4 Motor Starters (3 Point and 4 Point Starters) - Protective Devices - Calculation of Starters Steps for D.C Shunt Motors

###### UNIT V :TESTING OF DC MACHINES

5.1 Losses – Constant & Variable Losses - Calculation of Efficiency - Condition for Maximum Efficiency

5.2 Methods of Testing – Direct, Indirect – Brake Test – Swinburne’s Test – Hopkinson’s Test – Field’s Test – Retardation Test in a D.C. Motor Test