Introduction

• Brief theory of operation of a polyphase motor
• Motor output and torque
• Motor ratings and frame sizes
• Preferred ratings at different voltages
• Influence of service conditions on motor performance
• No-load performance Effect loading on motorperformance
• Effect of steel laminations on core losses
• Circle diagram
• Types of induction motors
• Mounting of motors
• Enclosures
• Weatherproof (WP) motors
• Degree of protection
• Cooling systems in large motors
• Single phase motors
• Theory of operation
• Energy conservation , energy auditing and energy efficient motors (EEM)

• Motor speed-torque curve
• NEMA rotor designs
• Special designs of rotors
• Effect of starting current on torque
• Load torque or opposing torque
• Selection of motors
• Time of start-up and its effect on motor performance
• Thermal withstand time
• Braking
• Inching or jogging
• Number of starts and stops

• Duty cycles Continuous duty (CMR) (S1)
• Periodic duties
• Factor of inertia (FI)
• Heating and cooling characteristic curves
• Drawing the thermal curves
• Rating of short-time motors
• Equivalent output of short time duties
• Shock loading and use of a flywheel

• Direct on-line starting (DOL)
• Reduced voltage starting

• Important features of a slip-ring motor
• Starting of slip-ring motors
• Hypothetical procedure to calculate the rotor resistance
• Speed control of slip-ring motors
• Moving electrode electrolyte starters and controllers

• Speed control in squirrel cage motors
• Speed control through solid-state technology
• V/f control (speed control at constant torque)
• Phasor (vector) control
• Use of phasor control for flux braking
• Control and feedback devices
• Evolution of solid-state technology
• Conduction and commutation
• Circuit configurations of semiconductor devices
• Smoothing of ripples in the d.c. link
• Providing a constant d.c. voltage source
• Providing a constant current source
• Generation of harmonics, over-voltages and voltage surges in a static device switching circuit and to mitigate their effects
• PWM inverter drives causing shaft currents
• Energy conservation using static drives
• Application of static controllers
• Speed variation through variable-speed fluid couplings
• Static drive versus fluid coupling
• D.C. drives S Retrofitting of EE motors and drives

• Textile motors
• Crane motors
• Determining the size of motor
• Sugar centrifuge motors
• Motors for deepwell pumps
• Motors for agricultural application
• Surface-cooled motors
• Torque motors or actuator motors
• Vibration and noise level
• Service factor
• Motors for hazardous locations
• Specification of motors for Zone 0 locations
• Specification of motors for Zone 1 locations
• Motors for Zone 2 locations
• Motors for mines, collieries and quarries
• Intrinsically safe circuits, type Ex. ‘i’
• Testing and certifying authorities
• Additional requirements for critical installations
• Motors for thermal power station auxiliaries
• Selection of a special-purpose motors
• Induction generators

• Direct or rigid couplings
• Flexible couplings
• Delayed-action couplings
• Construction and principle of operation
• Belt drives
• Checking the suitability of bearings
• Suitability of rotors for pulley drives

• Insulating materials and their properties
• Ageing of insulation
• Practices of insulation systems
• Procedure for vacuum pressure impregnation
• Maintenance of insulation
• Monitoring the quality of insulation of MV formed coils and resin-poorwindings during manufacturing

• Installation of bearings and pulleys
• Important checks at the time of commissioning
• Maintenance of electric motors and their checks
• Maintenance of bearings
• General problems in electric motors and their remedy
• Winding temperature measurement at site
• Analysis of insulation failure of an MV motor at a thermal power station

• Philosophy of quality systems
• Transition to ISO 9001(2000)
• Testing of electrical machines
• Procedure for testing
• Load test
• No-load test
• Tolerances in test results
• Certification of motors used in hazardous locations

• Purpose
• Unfavorable operating conditions
• Fault conditions
• Protection
• Single-device motor protection relays
• Summary of total motor protection
• Motor protection by thermistors
• Monitoring of a motor’s actual operating conditions
• Switchgears for LV motors
• Selection of main components
• Fuse-free system
• Switchgears for MV motors
• Microprocessor based devices (IEDs) and intelligent starters

APPENDIX Rule of thumb for everyday use

• Application
• Types of assemblies
• Conventional types of switchgear and control gear assemblies (also referred to as switchboards)
• Compact switchgear assemblies
• Intelligent switchboards
• Design parameters and service conditions for a switchgear assembly
• Determining fault level of a system and its duration
• Energy based discrimination
• Deciding the ratings of current-carrying equipment, devices and components
• Designing a bus system
• Designing a switchgear assembly
• HV switchgear assemblies
• Protection schemes
• General guidelines during installation and maintenance of a switchgear or a controlgear assembly
• Power circuits and control scheme diagrams

APPENDIX Painting procedure of switchgear and controlgear assemblies and treatment of effluent

• Philosophy of quality systems
• Use of environment friendly substances (RoHS)
• Recommended tests
• LV impulse test
• Procedure for type tests
• Procedure for routine tests
• Procedure for field tests
• Introduction to mechanical impact test, internal arc test and EMC/EMI (electromagnetic compatibility and emission) tests
• An introduction to earthquake engineering and testing procedure
• A passing reference to tsunami

• Introduction
• Types of Transformers
• Common features of a voltage and a current transformer
• General specifications and design considerations for voltage transformers
• Precautions to be observed while installing a voltage transformer
• Current transformers
• Short-time rating and effect of momentary peak or dynamic currents
• Summary of specifications of a CT
• Precautions to be observed when connecting a CT
• Test requirements
• Nonconventional methods of current measurement (sensors and transducers)
• Rogowski coils

• Introduction
• DG set
• Operating parameters
• Theory of operation
• Guidelines on the selection of a DG set
• Types of loads
• Starting of a DG set
• Protection of a DG set
• Parallel operation
• Procedure of parallel operation
• Fault levels and grounding of generators
• Recommended protection for a synchronizing scheme
• Load sharing by two or more generators
• Total automation through PLCs

APPENDIX Selection of power cables PVC, paper insulated and XLPE and ampacity

• Introduction
• Temporary over-voltages
• Voltage surge or a transient
• Transient stability of overhead lines
• Causes of voltage surges
• Definitions
• Causes of steep rising surges
• Effect of steep-fronted TRVs on the terminal equipment (motor as the basis)
• Determining the severity of a transient
• Protection of rotating machines from switching surges
• Theory of surge protection (insulation coordination)
• LV surge protection and surge protection devices (SPDs)

• Surge arresters
• Electrical characteristics of a ZnO surge arrester
• Basic insulation level (BIL)
• Protective margins
• Protective level of a surge arrester
• Selection of gapless surge arrester
• Classification of arresters
• Surge protection of motors
• Pressure relief facility
• Assessing the condition of an arrester

• Circuit interrupters
• Theory of circuit interruption with different switching mediums (theory of deionization)
• Theory of arc plasma
• Circuit breaking under unfavorable operating conditions
• Circuit interruption in different mediums
• HV and LV vacuum contactors
• Current chopping
• Virtual current chopping
• Containing the severity of switching surges
• Comparison of interrupting devices
• Gas insulated switchgears (GIS)
• Retrofitting of old installations

• Theory of over voltages
• Analysis of ungrounded and grounded systems
• The necessity of grounding an electrical system
• Analysis of a grounded system
• Arc suppression coil or ground fault neutralizer
• Ground fault factor (GFF)
• Magnitude of temporary over-voltages
• Insulation coordination
• Application of different types of grounding methods (for MV, HV and EHV systems)
• Important parameters for selecting a ground fault protection scheme

• Protection of a domestic or an industrial single phase system
• Ground fault on an LV system
• Ground fault protection in hazardous areas
• Ground leakage in an HV system
• Core-balanced current transformers (CBCTs)
• Ground fault (G/F) protection schemes
• Grounding systems and their choices

• Grounding electrodes
• Resistivity of soil (r)
• Measuring the ground resistance
• Metal for the grounding conductor
• Jointing of grounding conductors
• Maintenance of grounding stations
• Grounding practices in a power generating station
• Tolerable potential difference at a location
• Voltage gradients
• Determining the leakage current through a human body
• Measuring the average resistivity of soil
• Improving the performance of soil
• Determining the ground fault current
• Designing a grounding grid

• Introduction
• Application of power capacitors
• Effect of low PF
• Other benefits of an improved power factor
• Behaviour of a power capacitor in operation
• Generation of triple harmonics in an inductive circuit
• Generation of harmonics by a power electronic circuit
• Resonance
• Effective magnitude of harmonic voltages and currents
• When harmonics will appear in a system
• Filter circuits: suppressing harmonics in a power network
• Excessive charging currents (switching inrush or making currents)
• Limiting the inrush currents
• Capacitor panel design parameters
• Capacitor rating for an induction motor
• Location of capacitors
• Automatic PF correction of a system
• Switching sequences
• PF correction relays

• Electromagnetic compatibility (EMC)
• Electromagnetic interferences (EMI)

• Capacitors for improving system regulation
• Series capacitors
• Rating of series capacitors
• Advantages of series compensation
• Analysis of a system for series compensation
• Reactive power management
• Influence of line length (Ferranti effect)
• To optimize the power transfer through reactive control
• Transient stability
• Auto-reclosure scheme for transient stability
• Switching of large reactive banks
• Automation of power network for dynamic stability through SCADA system
• Serial data transmission and communication interfaces
• Introduction to communication protocols
• Security of SCADA system

• Making a capacitor element
• Special purpose capacitors
• A critical review of internally protected capacitor units
• Self-healing capacitors
• Making a capacitor unit from elements
• Making capacitor banks from capacitor units
• Rating and selection of components for capacitor duty
• Fast discharge devices

• Protection and safety requirements
• Installation and maintenance of capacitor units
• Test requirements

• Introduction
• Types of power reactors
• Selection
• Design criterion and I – f characteristics of different types of reactors
• Applications

• Introduction
• Types of metal-enclosed bus systems
• Non-conventional compact and sandwich low loss bus systems for LV and HV systems
• Partially isolated bus systems for HV systems
• Design parameters and service conditions for a metal enclosed bus system
• Short-circuit effects
• Service conditions
• Other design considerations for aluminium and copper busbars
• Skin effect
Proximity effect
• Sample calculation for designing a 2500 A non-isolated phase aluminium busbar system

• Precautions in mounting insulators and conductors
• Types of joints
• Making a joint
• Bending of busbars

• Physical and electrical properties of aluminium and copper conductors
• Ampacity tables of copper and aluminium conductors

• An isolated phase bus (IPB) system
• Constructional features
• Special features of an IPB system
• Enclosure heating
• Natural cooling of enclosures
• Continuous rating
• Forced cooling
• Influence of a space field on the metallic structures
• Fault level
• Voltage drop
• Forming of sections for IPB systems
• Determining the section and size of conductor and enclosure
• Sample calculations

• Philosophy of quality systems
• Recommended tests
• Impulse test on LV bus system
• New safety measures and tests prescribed by IEC
• Procedure for type tests
• Routine tests
• Field tests