EEM FROM EA AND DSM

1. ENERGY AUDIT AND DEMAND SIDE MANAGEMENT
FINAL YEAR
DEPARTMENT OF EEE
PREPARED BY
HARIKA.A
AITS-TPT
2/24/2015 1

2. UNIT-3
ENERGY EFFICIENT MOTORS
2/24/2015 2

3. CONTENTS
 INTRODUCTION
 FACTORS AFFECTING EEM
 EFFICIENCY & LOSS DISTRIBUTION
 CONSTRUCTIONAL DETAILS
 RMS HP LOADING
 VOLTAGE VARIATION-UNBALANCE
 VARIABLE DUTY CYCLE
 MOTOR ENERGY AUDIT
2/24/2015 3

4. INTRODUCTION
 Energy efficient motors (EEM) are the ones in which,
design improvements are incorporated specifically to
increase operating efficiency over standard motors.
Energy-efficient motors operate with efficiencies that
are typically 4 to 6% higher than the standard motors.
2/24/2015 4

5. FACTORS AFFECTING EEM
STATOR AND ROTOR CU LOSSES
CORE LOSSES
FRICTION & WINDAGE LOSSES
STRAY LOAD LOSSES
2/24/2015 5

6. Power Loss Area Efficiency Improvement
1. Stator I2R
Use of more copper and larger conductors
increase cross sectional area of stator
windings. This lowers resistance (R) of the
windings and reduces losses due to current
flow (I).
Rotor I2R
Use of larger rotor conductor bars increase size of
cross section, lowering conductor resistance (R) and
losses due to current flow (I).
Iron Use of thinner gauge, lower loss core steel
reduces eddy current losses. Longer core adds
more steel to the design, which reduces losses
due to lower operating flux densities.
Friction & Windage loss
Use of low fan design reduces losses due to air
movement.
Stray load losses Use of optimized design of slots numbers2/24/2015 6

7. Efficiency & loss distribution
Motor performance
Power factor
Voltage variation
Motor load
2/24/2015 7

8. Constructional details
 By increasing the amount of copper in the motor (≥60%)
which reduces the resistance (Ohmic) loss in the winding &
temperature rise. Performance improves because of increased
thermal mass.
 Use of more & thinner laminations of high quality motor
steel reduces core losses in the stator and rotor.
 Narrowing of air gap between stator and rotor increases the
intensity of magnetic flux, thereby improving the motor
ability to deliver the same torque at reduced power.
Increasing the length of stator and rotor increases the net
flux linkages in the air gap to the same effect.
 More complex rotor bar designs enable good starting torque
with efficient full speed operation.
 Improved overall design reduces windage losses and stray
load losses.
2/24/2015 8

9. RMS HP LOADING
This factor decides whether the motor will be
applicable for a particular cyclicing operation or not.
The RMS calculations take into account the fact that
heat build up within the motors is very much greater
at a 50% overload than it is under normal operating
conditions
2/24/2015 9

10. Calculation of RMS HP loading
2/24/2015 10

11. Contd..,
2/24/2015 11

12. 2/24/2015 12

13. 2/24/2015 13

14. Voltage variation & unbalance
Voltage unbalance is defined by the National Electrical
Manufacturers Association (NEMA) as 100 times the absolute
value of the maximum deviation of the line voltage from the
average voltage on a three-phase system, divided by the average
voltage.
2/24/2015 14

15. Contd..,
 Voltage unbalance degrades the performance and
shortens the life of motor.
 Voltage unbalances at the motor stator terminals causes
phase current unbalance far out of proportion the
voltage unbalance
 Unbalanced currents lead to torque overheating, which
results in a shorter winding insulation life
2/24/2015 15

16. Common causes for unbalance
 Faulty operation of power factor correction
equipment
 Unbalanced or unstable utility supply
 Unbalanced transformer bank supplying a three-
phase load that is too large for the bank
 Unidentified single-phase to ground faults
 An open circuit on the distribution system primary
2/24/2015 16

17. Contd..,
2/24/2015 17

18. Motor Energy Audit
 Drive power is huge- think big,
 Motors are part of a system –think systems,
 Optimize the applications &process-deliver
service,
 The further the downstream savings, the higher is
the upstream benefits-start downstream,
 Pursue integration package of savings
opportunities rather than isolated measures
because many savings are inter –dependent –
integrate measures
2/24/2015 18

19. Contd..,
 Collection of nameplate details of motor and load equipment
 Measurement of voltage, current, power, apparent power, power
factor, frequency and annual operating hours for major loads.
 Calculation of load factor for major loads.
 Checking for light loads on large motors
 Check if valves are always used for flow control in pumps, fans and
blowers.
 Check if flow from pumps, fans and blowers are changing
continuously.
 Check if the set discharge pressure is at the lowest permissible limit
of operation in the compressor.
 Check for proper maintenance of major equipment i.e. cleaning
measuring temperature, dust, vibration, noise, lubrication and
coupled condition.
2/24/2015 19

20. Power factor correction at motor end
 Capacitors connected in parallel (shunted) with the
motor are typically used to improve the power factor
 The impacts of PF correction include reduced KVA
demand (and hence reduced utility demand
charges), reduced I2R losses in cables upstream of
the capacitor (and hence reduced energy charges),
reduced voltage drop in the cables
2/24/2015 20

21. Contd..,
 The size of capacitor required for a particular motor
depends upon the no-load reactive KVA (KVAr) drawn
by the motor
 Required capacitive kVAr increases with decrease in
speed of motor, as the magnetizing current
requirement of a low speed motor is more compared to
the high speed motor for the same HP.
2/24/2015 21

22. Duty cycle
 It is a cycle that an entity remains in active state for a
total time period T is called duty cycle . For instance
consider 1% of duty cycle i.e one cycle is in active state
out of 100 .therefore
Ton+ Toff = Duty cycle
2/24/2015 22

23. Need for using controls
 Oversized motor
 Varying Load
Adjustable speed capability can significantly
improve productivity of many manufacturing
processes by reducing scrap, enabling quality
manufacturing during transition times and allowing
more control over start up and shut down.
2/24/2015 23

24. THANK YOU
2/24/2015 24