The document discusses electric motors and motor efficiency. It provides details on how electric motors work using electromagnetism to convert electricity into mechanical motion. It then discusses the components and operation of simple DC motors and 3-pole motors. The document also discusses how motor efficiency is important and outlines standards used to determine motor efficiency. It provides an overview of efficiencies for different motor sizes and describes ways to improve motor efficiency, such as using more efficient NEMA Premium motors.

1. Electric MotorsElectric Motors
ESM 288ESM 288
Betty SetoBetty Seto
Kat WuelfingKat Wuelfing

2. Electric MotorElectric Motor
•• Converts electricity into mechanical motionConverts electricity into mechanical motion
•• Works by electromagnetismWorks by electromagnetism
•• Lorentz Force LawLorentz Force Law
Current flowing through aCurrent flowing through a
wire produces a magneticwire produces a magnetic
field (labeled M here) aroundfield (labeled M here) around
the wire.the wire.

3. Simple DC MotorSimple DC Motor
•• Armature or rotorArmature or rotor
•• CommutatorCommutator
•• BrushesBrushes
•• AxleAxle
•• Field magnetField magnet
•• DC power supplyDC power supply

4. Simple DC MotorSimple DC Motor
•• A magnetic field is generatedA magnetic field is generated
around the armature.around the armature.
•• The left side of the armature isThe left side of the armature is
pushed away from the leftpushed away from the left
magnet and drawn toward themagnet and drawn toward the
right, causing rotation.right, causing rotation.
•• When the armature becomesWhen the armature becomes
horizontally aligned, thehorizontally aligned, the
commutatorcommutator reverses thereverses the
direction of current through thedirection of current through the
coil, reversing the magneticcoil, reversing the magnetic
field.field.
•• Momentum keeps the motorMomentum keeps the motor
moving the right direction.moving the right direction.
•• The process then repeats.The process then repeats.

5. 3 Pole Motor3 Pole Motor
•• A motor can have anyA motor can have any
number of polesnumber of poles
•• Most common formMost common form
•• DoesnDoesn’’t get stuck int get stuck in
horizontal positionhorizontal position
•• In 2 pole, alwaysIn 2 pole, always
shorts out the batteryshorts out the battery
when thewhen the commutatorcommutator
flips the fieldflips the field

6. Examples of everyday motors
• EVERYTHING!!!!!
• At home:
• The fan over the stove and in the microwave oven
• The dispose-all under the sink
• The blender
• The can opener
• The refrigerator - Two or three in fact:
– one for the compressor,
– one for the fan inside the refrigerator,
– as well as one in the icemaker
• The mixer
• The tape player in the answering machine
• Probably even the clock on the oven
• The washer
• The dryer
• The electric screwdriver
• The vacuum cleaner and the Dustbuster mini-vac
• The electric saw
• The electric drill
• The furnace blower
• Even in the bathroom, there's a motor in:
• The fan
• The electric toothbrush
• The hair dryer
• The electric razor
• Your car is loaded with electric motors:
• Power windows (a motor in each window)
• Power seats (up to seven motors per seat)
• Fans for the heater and the radiator
• Windshield wipers
• The starter motor
• Electric radio antennas
• Motors in all sorts of places:
• Your iPod
• Several in the VCR
• Several in a CD player or tape deck
• Many in a computer
• Most toys that move
• Electric clocks
• The garage door opener
• Aquarium pumps

7. Motor efficiency mattersMotor efficiency matters
• In U.S. Industry, electric motors consume:
– ~680 billion kWh/year
– ~63% of all industrial electricity consumption
– ~23% of all U.S. consumption
Source: U.S. DOE. Energy Efficiency and Renewable Energy (EERE).
www.pumps.org/public/member_services/presentations/2005_spring/electric_motor_efficiency.pps
• These percentages are typically higher in
developing countries, while the motors are
typically less efficient

8. How is power lost in a motor?
• Mechanical (friction and windage) losses
– friction in bearings and seals and power consumed by
the motor cooling fan
• Magnetic (core) losses
– hysteresis and eddy current losses in steel
laminations of the stator and rotor
• Electrical (I2R) losses
– Stator winding losses
– Rotor conductor bar losses
• Stray losses
– miscellaneous losses associated mainly with
electromagnetic radiation
Source: U.S. DOE. Energy Efficiency and Renewable Energy (EERE).
www.pumps.org/public/member_services/presentations/2005_spring/electric_motor_efficiency.pps

9. U.S. standard for determinationU.S. standard for determination
of motor efficiency: IEEE 112of motor efficiency: IEEE 112--BB
•• Based on Energy Policy Act legislationBased on Energy Policy Act legislation
(The value of efficiency is then normally converted from a decimal fraction to a percent for convenience.)
•• Need for a standard:Need for a standard:
–– Efficiency changes as greaseEfficiency changes as grease ““breaks inbreaks in””
–– Output and input power can varyOutput and input power can vary
–– Readings of speed, torque, volts, amperes, watts areReadings of speed, torque, volts, amperes, watts are
not steady of constant valuesnot steady of constant values
Source:Source: http://www.iprocessmart.com/leeson/leeson_epact_motor_testing.hthttp://www.iprocessmart.com/leeson/leeson_epact_motor_testing.htmm

10. Overview of motor efficiencies
• The following table of results from three different
testing standards:
Test Method 15 HP 75 HP 800 HP 1500 HP
IEEE 112 B (U.S.) 87.4 90.0 95.9 95.9
IEC 34-2 (International) 89.2 92.7 95.6 96.0
JEC 37 (Japanese) 90.1 93.1 95.9 96.8

11. Improving motor efficienciesImproving motor efficiencies
• According to U.S. DOE, use of only “Premium
Efficiency” motors could save ~20 billion
kWh/year in the U.S.
– Covers wide-range of motor specifications
– 680 billion kWh/year consumption by electric motors
• Joint specification by:
– National Electrical Manufacturers Association
(NEMA )
– Consortium for Energy Efficiency (CEE)

12. NEMA Premium® motors
Example One
50 hp, 1800 rpm,
460 V
Example Two
25 hp, 1800 rpm,
460 V
EPAct Standard NEMA Premium EPAct Standard
NEMA
Premium
Full Load Efficiency 93.1* 94.5 92.4 93.6
Efficiency (at 75%
load)
93.6 95.1 93.1 94.1
Demand Reduction
(at 75% load)
- 0.47 kW - 0.16 kW
Meets EPAct? yes yes yes yes
Incremental Motor
Cost
- $176 - $96
Energy Savings at
75% Load (6000
hrs/year)
- 2,829 kWh/y - 958 kWh/y

13. • Expanding the definition of “motor”
• Solar powered nano motor
The Future…
http://www.spacemart.com/reports/Nano_World_First_Solar_Powered_http://www.spacemart.com/reports/Nano_World_First_Solar_Powered_Nano_Motor.htmlNano_Motor.html

14. Thank you.
The end.

15. Background: AC Induction Motor
• This is the most commonplace motor. It has a
rotating stator field. The rotor has imbedded
electroconductive bars resembling a pet rodent
exercise wheel, which inspired the name, “squirrel
cage”. The rotating stator field induces current in the
cage creating a magnetic field which causes the rotor
to follow the stator field.
First Induction
Motor, 1888
Inventor Nikola
Tesla
1894 Induction
Motor. World’s
largest when
new. 65 HP

16. How is efficiency determined?How is efficiency determined?
•• IEEE 112IEEE 112--B (United States)B (United States)
•• IEC IEC60034.2 (InternationalIEC IEC60034.2 (International ElectrotechnicalElectrotechnical
Commission)Commission)
•• JECJEC--37 (Japanese37 (Japanese ElectrotechnicalElectrotechnical Committee)Committee)
•• CC--390 (Canadian Standards Association)390 (Canadian Standards Association)
There are different standards in useThere are different standards in use
around the world for thearound the world for the
determination of motor efficiency.determination of motor efficiency.
They yield slightly different results.They yield slightly different results.
Source: U.S. DOE. Energy Efficiency and Renewable Energy (EERE).
www.pumps.org/public/member_services/presentations/2005_spring/electric_motor_efficiency.pps

17. What’s in an efficient motor?
Same components; just more and better
materials and closer tolerances.
Larger wire gage – Lower stator winding
loss
Longer rotor and stator – Lower core
loss
Lower rotor bar resistance – Lower rotor
loss
Smaller fan – Lower windage loss
Optimized air gap size – Lower stray
load loss
Better steel with thinner laminations --
Lower core loss
Optimum bearing seal/shield – Lower
friction loss

18. A Useful Tool – MotorMaster+
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