Three phase induction motor By Mitesh Kumar

Three phase induction motor By Mitesh Kumar

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  PRESENTATION ON THREE PHASEINDUCTION MOTOR • PRESENTED BY: • MITESH KUMAR • 13/EIE/26 • B.TECH(5TH SEM) • 10300513026 • Appliied Electronics & instrumentation Engineering Haldia Institute Of Technology
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  INDUCTION MOTOR
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  INTRODUCTION • Three-phase inductionmotors are the most common and frequently encountered machines in industry – simple design, rugged, low-price, easy maintenance – wide range of power ratings: fractional horsepower to 10 MW – run essentially as constant speed from no-load to full load – Its speed depends on the frequency of the power source
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  CONSTRUCTION • An inductionmotor has two main parts – a stationary stator – a revolving rotor • Two basic design types depending on the rotor design – squirrel-cage: conducting bars laid into slots and shorted at both ends by shorting rings. – wound-rotor: complete set of three-phase windings exactly as the stator. Usually Y-connected, the ends of the three rotor wires are connected to 3 slip rings on the rotor shaft. In this way, the rotor circuit is accessible
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  Squirrel cage rotor Woundrotor
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  PRINCIPLE OF OPERATION •This rotating magnetic field cuts the rotor windings and produces an induced voltage in the rotor windings • Due to the fact that the rotor windings are short circuited, for both squirrel cage and wound-rotor, and induced current flows in the rotor windings • The rotor current produces another magnetic field • A torque is produced as a result of the interaction of those two magnetic fields
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  ROTATING MAGNETIC FIELD •Balanced three phase windings, i.e. mechanically displaced 120 degrees form each other, fed by balanced three phase source • A rotating magnetic field with constant magnitude is produced, rotating with a speed Where fe is the supply frequency and P is the no. of poles and nsync is called the synchronous speed in rpm (revolutions per minute) 120 e sync f n rpm P 
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  SYNCHRONOUS P 50 Hz60 Hz 2 3000 3600 4 1500 1800 6 1000 1200 8 750 900 10 600 720 12 500 600
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  ROTATING MAGNETIC FIELD
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  ROTATING MAGNETIC FIELD
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  APPLICATION OF INDUCTIONMOTOR • Squirrel cage induction motor • Squirrel cage induction motors are simple and rugged in construction, are relatively cheap and require little maintenance. Hence, squirrel cage induction motors are preferred in most of the industrial applications such as in • Lathes • Drilling machines • Agricultural and industrial pumps • Industrial drives.
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  CONT.... • Slip ringinduction motors • Slip ring induction motors when compared to squirrel cage motors have high starting torque, smooth acceleration under heavy loads, adjustable speed and good running characteristics. • They are used in • Lifts • Cranes • Conveyors , etc.,
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  THANK YOU