Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Practical Motor Protection, Control and Maintenance Technologies

3,341 views

Published on

It is estimated that electrical drives and other rotating equipment consume about 50% of the total electrical energy consumed in the world today (and this figure increases to 70% if you only consider industry). The cost of maintaining electrical motors can be a significant amount in the budget item of manufacturing and mining industries. This workshop gives you a thorough understanding of electrical motor’s protection, control and maintenance and gives you the tools to maintain and troubleshoot electrical motors.

You will gain a fundamental understanding of the protection, control and maintenance of electric motors and drives. Typical applications of electric motors in mining, manufacturing, materials handling and process control are covered in detail. The concluding section of the workshop gives you the fundamental tools in troubleshooting motors confidently and effectively.

MORE INFORMATION: http://www.idc-online.com/content/practical-motor-protection-control-and-maintenance-technologies-49

Published in: Engineering
  • Be the first to comment

Practical Motor Protection, Control and Maintenance Technologies

  1. 1. Practical Motor Protection, Control and Maintenance Technologies Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  2. 2. Fundamentals of motor technology and construction • Basic principles of rotating electric machines • Fundamental principles of speed control • Efficiency, torque, inertia, horsepower/power factor • Torque-speed curves • Induction/synchronous/wound rotor types • Basic construction and physical configuration, windings • Principles of operation and performance Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  3. 3. Motoring Action 1. As voltage is applied to the stationary conductors, magnetic field is produced. 2. This magnetic field in turn induces voltage in the rotor conductors, in case of some motors (induction motors) or voltage is externally applied to the rotor conductors. 3. This voltage also produces magnetic field. 4. The magnetic field of the stator and rotor, together, put the rotor in running condition. Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  4. 4. Depiction of a motoring action Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  5. 5. Electric machine concepts • Electrical machines (either a motor or a generator) can be broadly classified as DC Machines and AC Machines – depending on the nature of supply given to them. • An electrical machine can be interchangeably associated with either a motor or a generator. • The fundamentals for a particular category (like DC or Synchronous) are identical for both the generator and motor. Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  6. 6. Simple depiction of a motor Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  7. 7. A simple DC machine • A simple DC machine has a current carrying coil supported in between two permanent magnets • These magnets create the necessary flux (opposite poles facing each other) • Poles of a magnet, North & South, are always together • Accordingly Poles of a motor are expressed in pairs • The coil – armature – can rotate freely inside Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  8. 8. Electromagnetic circuit of a DC machine Armature: The coil ends are connected to a DC source - Current flows through the circuit - Coils behave like a bar magnet - Results in Magnetic flux Field: Produces flux lines – across the Poles Rotation: As a result of Forces of attraction / repulsion between two fields. Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  9. 9. Electromagnetic circuit of a DC machine Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  10. 10. Electromechanical features of DC machines •Yoke: Motor housing •Stator: Houses Field winding Poles & Interpoles •Rotor: Armature carrying the commutator apart from the rotating shaft •Main pole: Houses field winding •Commutator: Rotating, current transferring agent. Helps in developing a stationary field by the rotating armature •Brushes: Stationary, current carrying conductors making contact with the commutator •Pole Shoe: Helps in maximizing the flux distribution Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  11. 11. Electromechanical features of DC machines Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  12. 12. Commutator of a DC machine •Used only in DC Machines •Extends supply to the Armature •Any electrical machine will have two magnetic fields developed by its: •Stator and •Rotor •Both the fields of a DC motor are Stationary •Acts as a bridge between stationary supply wires and rotating Armature Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  13. 13. Simple cross sectional view of a DC machine Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  14. 14. Speed characteristics of various types of DC Motors Shunt: Most commonly used – Speed drops slowly as the motor is loaded. Series: Speed drops heavily as the motor is loaded Develops very high speeds at low load Used mainly for traction Compound: Cumulative – in between Shunt and Series Differential – speed rises with the load applied Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  15. 15. Speed characteristics of various types of DC Motors Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  16. 16. Representation of apparent power and real power Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  17. 17. Torque characteristics of various types of Motors •A curve drawn between the TORQUE developed by a Motor against the speed / loading (current) •Useful in the selection of appropriate motors for a particular Load requirement •A proper match – gives the best performance •A mismatch – havoc for running the Plant •Helpful in estimating the acceleration time Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  18. 18. Torque characteristics of various types of DC Motors Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  19. 19. Torque characteristics of AC Induction Motors Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  20. 20. Torque characteristic of a Synchronous Motor Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  21. 21. Squirrel Cage Induction Motor (SCIM) •It is the most common type of AC motor. •Known as the workhorse of Modern Industry •It is the most cost effective motor •Can be designed for any kind of environment. •Construction of the rotor gives this name. •The rotor consists of a series of conducting bars laid into slots carved in the face of the rotor and shorted at either end by large shorting rings. Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  22. 22. Simple view of squirrel cage induction rotor Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  23. 23. Slip Ring Induction Motor •The motor starts with a full resistance bank •As speed of the motor increases, the resistances are shorted, one by one •As the motor reaches full speed, the whole bank of resistance is shorted out and the motor now runs alike a squirrel cage induction motor •Very much useful to develop high starting torque •Reduced starting current puts less burden on the power system Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  24. 24. Simple view of slip ring induction rotor Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  25. 25. Synchronous motor •Synchronous motor is a constant speed motor •Can be used to correct the power factor of the 3-phase system. •Like the Induction motor in terms of the stator, the synchronous machine has either a permanent magnet arrangement or an electromagnet (with current supplied via slip rings) rotor. •In simple terms, the rotor will keep locking with the rotating magnetic field in the stator. •In many synchronous machines, a squirrel cage is in incorporated into the rotor for starting. Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  26. 26. Single phase induction motor •This motor is used mostly in small sizes, where polyphase current is not available •Characteristics are not as good as the polyphase motor and for size larger that 10 HP, the line disturbance is likely to be objectionable •These motors are commonly used for light starting and for running loads up to 1/3 HP Capacitor and repulsion types provide greater torque and are built in sizes up to 10 HP. •Mostly finds application in domestic sector Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  27. 27. Shaded pole single phase induction motor Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  28. 28. Assembly details of a typical AC induction motor Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  29. 29. Stator and rotor laminations • The magnetic path of a motor comprises a set of slotted steel laminations • These silicon steel laminations are pressed into the cylindrical space inside the outer frame • The magnetic path is laminated to reduce eddy currents.... lower losses and lower heating • A set of insulated electrical windings, which are placed inside the slots of the laminated magnetic path • Rotor laminations are varied based on the type of torque characteristic to be realized Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  30. 30. Speed-Torque curves of Motor Vs Load • The machine and the load are the two components of an electro-mechanical energy conversion system. • The machine characteristics play a very important role in the operating behavior of the entire system. • The steady operating point is the point where the speed torque characteristics of the load and the motor intersect each other. • The drive system will settle to a speed corresponding to the point of intersection of these two curves Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  31. 31. Speed-Torque curves of Motor Vs Load Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  32. 32. Drive systems engineering • At the time of engineering the drive systems, following shall be considered for both the Motor as well as the Load: – the speed / torque characteristics – the speed / power characteristics • Load characteristics can be classified as – Constant Torque – Constant Horsepower – Squared-Exponential Loads - torque varies directly as the speed, and power as the square of speed – Cubed-Exponential Loads - torque varies as the square of speed, and power as the cube of speed Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss
  33. 33. DO YOU WANT TO KNOW MORE? If you are interested in further training or information, please visit: http://idc-online.com/slideshare Technology www.idc-online.com/slideshare Technology TTrraaiinniinngg tthhaatt Wwoorrkkss

×