Electric motors impact in almost every form of modern life. Electric motors are definitely being used at some point in almost all industries for producing modern products. Nowadays, older motors are being replaced by advanced ones for obtaining better results and performances.
This course will guide the student to know about the basic principles of motors, how to protect them, variable speed drives and power electronic components.
After completion of this course, students will have a clear idea about the basic working principle of motors, their types, main causes of damage and ways to protect them.
WHO SHOULD COMPLETE THIS COURSE?
- Electronics engineers
- Power system analysts
- Instrumentation engineers/ technicians
- Electricians/Operators
- Electrical engineers
- Instrumentation & control engineers
COURSE OUTLINE
FUNDAMENTALS & BASIC PRINCIPLES OF MOTORS
- Introduction – Motor
- Review – Magnetic Fields
- Force on a conductor in a magnetic Field
- Fleming’s left hand rule – Motor
- Torque on a conductor in a magnetic Field
- A generator or a Motor action
- Basic principles of rotating electrical machines
- Fundamental electromechanical converter
CLASSIFICATION & DC MOTOR FUNDAMENTALS
- Classification of motors
- Types of electrical machine
- Configurations of the three types of electric machine
- Simple depiction of a motor
- DC motor fundamentals
- Electromagnetic circuit of a DC machine
- Electromechanical feature of a DC machine
- Commutator of a DC machine
- Fundamental principles of speed control
- Speed characteristics of various DC motors
- Efficiency and Motor losses
- Classification of losses in rotating machines
- Inertia, horsepower and power
- Torque-speed curves
AC INDUCTION MOTOR
- AC Induction motor
- Motor, Rotor & Stator construction
- Construction: Squirrel cage rotor, wound rotor
- Why does the rotor of induction motor rotate?
- Relation between no. of poles, speed & frequency’
- Equivalent circuit of AC motor
- Current vectors and motor performance
- Maximum torque
- Torque – speed curve
- Motor acceleration
SYNCHRONOUS MOTOR
- Synchronous Motor
- Cross sectional view of synchronous motor
- Synchronous motor action
- Power factor v/s Excitation
- Applications Synchronous Motor
- Losses & efficiency of Synchronous Motor
- 3 phase Synchronous Motor
PROTECTION OF MOTOR
- Main causes for motor damage
- Motor protection
- Current sensing & thermal curve
- Differential protection
- Life of electrical motor
- New generation motor protection relays
- Overload protection for motor
- Short circuit protection of motors
- Ph – ground & Ph to Ph faults
- Stall protection
- Unbalanced supply voltage
- Negative Sequence currents
- Derating factors
THREE PHASE INDUCTION MOTOR
- What is a 3-phase AC circuit
- Three phase motor advantages
- Efficiency of motors
- Losses in an induction motor
- Friction & windage loss
- Standards applicable to induction motors
- Rated load thermal, no load & load test
- The locked rotor test
- Drawbacks of braking arrangements
- Transmission & absorption dynamometers
- Block diagram – DC non-regenerative dynamometer
- Block diagram – DC regenerative dynamometer
VARIABLE SPEED DRIVES
- Need for VCD
- Benefits of variable speed
- Load torque & load ability curve
- Main types of VSD
- Electrical VSD
- Power electronic converters
- DC VSD
- AC VSD
OTHER ELECTRICAL VSD & VSD DESIGN
- Other electrical VSD systems
- Split control of induction motors
- Reduced voltage control
- Direct on line starter
- Reduced voltage control
- Typical connection of a star/delta starter
- Typical connection of an autotransformer start
- Motor & vector control
- Harmonic effects on rotating machine
- Acceleration torque
- Oil & gas applications
- Hazardous area electrical equipment marking
POWER ELECTRONIC COMPONENTS
- Basic definitions
- Power diodes
- VSD circuit input rectifier bridge
- Power Thyristor
COMMUTATION & GATE CONTROLLED POWER ELECTRONIC COMPONENTS
- Commutation
- Diode rectifier – DC voltage
- Line commutated Thyristor rectifier
- Gate commutated inverter
- Voltage source inverter
- PWM inverter
- 3-phase PWM inverter
- GTO Thyristor
- Bipolar Junction Transistor
- Field Effect Transistor
- Insulated Gate Bipolar Transistor
- Comparison of PF switches
EMC & PROTECTION OF CONVERTERS
- Main sources of EMI
- Electrical interference
- Harmonic distortion
- Power electronic converters
- 6 & 12 pulse rectifier connection
- Main converter harmonics
- Reducing harmonics
- Problems with HF PWM switching
- Reduction of emissions
- AC converter protection
- DC bus under/over –voltage
- Over current & temperature protection
- Motor thermal O/L protection
- Motor protection
- Current sensing
INSTALLATION & FAULT FINDING TECHNIQUES
- Environmental requirements & hazardous areas
- DE-rating for temperature
- Main cable & power supply cables
- Common cabling errors
- Stop/start control of AC drives
- Mounting in metal enclosures
- Natural & forced ventilation
- Recessed ventilation
- Commissioning
- Basic setting parameters
SELECTION OF AC CONVERTERS FOR VSD APPLICATIONS
- Selection of VVVF drives
- Basic selection procedures
- Torque loadability
- Nature of the machine load
- Variable torque loads – Pumps & Fans
- Constant torque loads – Conveyors
- Requirements for stopping
- DC injection breaking, dynamic & regenerative breaking
- Selection of Motor & Converter
CONTROL SYSTEM FOR VARIABLE SPEED DRIVES
- Overall control system
- Power supply requirements
- DC bus charging
- PWM rectifier bridge
- AC variable speed drives
- Open & closed loop control
- Cascaded loop control
- Vector control
- Sensor less vector control drives
- Field oriented flux-vector drives
- Current & speed feedback
