This document discusses electric motors and provides information on various types of electric motors including AC and DC motors. It describes how electric motors work by converting electric energy to mechanical energy using magnetic fields and winding currents. It also discusses the different losses that occur in induction motors including electrical losses from heat in the stator and rotor windings, magnetic losses in the iron, and mechanical losses from friction. The document notes that efficient motors can achieve the same output while consuming less power through improvements like more copper in the windings, reduced fan loss, higher quality steel, and an optimal air gap.

1. Electric motors
Presented at
MESCE KUTTIPPURAM
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2. Over view
• Electric motors
• Types of electric motors
• Losses in induction machines
• Motor efficiency
• Energy efficient motor
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3. ELECTRIC MOTORS
• Convert electric energy to mechanical energy
• Operate by the interaction between magnetic field and winding
current
• Operate in both motoring and braking mode
• Use in industrial fans ,pumps, machine tools etc..
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4. Types of electric motors
AC MOTOR DC
MOTOR
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5. AC MOTORS
Induction
motor
Synchronous
motor
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6. Induction motor
Three phaseSingle phase
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7. 7
DC MOTOR
• Permanent magnet DC motor
• Separately excited DC motor
• Series field wound DC motor
• Shunt field wound DC motor
• Compound motor

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Losses in induction machines
• Electrical losses due to heat produced in the stator and
rotor winding (copper losses)
• Magnetic loss in the iron due to hysteresis and eddy
current
• Mechanical loss due to friction in the bearing and
ventilation
• Stray load losses

9. Losses in Induction motor
Variable
losses
Fixed
losses
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10. Constant Losses
Iron or
Core loss
Mechanical
loss
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11. Iron losses
Eddy current
losses
Hysteresis
losses
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Mechanical losses
• Due to friction in the bearing and ventilation
• This losses vary slightly with load and speed
• This variation are considered to be negligible

13. Variable losses
Stator copper
loss
Rotor
copper loss
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14. Motor Efficiency
• Ratio between the shaft power out put to
the electrical input
• Ƞ = P out/P in
• Ƞm = (Pout )(746)/Pin
when Pout in hP
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15. Energy Efficient motors
• 2 to 8 percentage more efficiency than the standard
motor
• Same out put by consuming lesser amount of power
• Achieved by
1. More copper in the winding
2. Reduced fan loss
3. Higher quality thinner steel lamination
4. Optimal air gap between rotor and stator
5. Greater length high quality aluminum used
in the rotor frame 15

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