Please give seminar for energy efficient motors

Energy efficient motors
1. WELCOME
2. ENERGY EFFICIENT MOTORS Presented by M.jagadeesh
3. CONTENTS What is energy efficient motor(EEM) ? Difference between standard motor and energy efficient motor Need of an energy efficient motors Efficiency Maintenance Applications Advantages and disadvantages Conclusion
4. WHAT IS ENERGY EFFICIENT MOTOR? An "energy efficient" motor, simply put, is a motorthat gives you the same output strength byconsuming lesser amounts of powerEXPERIMENTAL RESULTSType of motor Annual Consumption of energy in kwhStandard motors 870Energy efficient motors 804.59
5. DIFFERENCE BETWEEN STANDARD MOTOR AND ENERGY EFFICIENT MOTOR More copper in the windings. Reduced fan loses. Energy efficient motors operate with efficiencies that are typically 2-6% higher than standard motors.
6. NEED:  When there is a new installation or modification to your plant.  Old motors are damaged and need rewinding.  Existing motors are underloaded or overloaded.  Protecting other devices.
7. EFFICIENCY
8. LOSSES :Losses are primarily of two types i.e. core and copper losses. Copper loss Core loss Friction and windage Loss Stray load loss
9. SAVINGS
10. Cost of energy efficient motors: Usually it is of normal cost and slightly more than the normal motors. It is about 15% to 30% more than the normal motors. In Future, the initial cost may be available at the same cost as a standard motor when the population of EE Motors increases
11. ADVANTAGES  Operate more satisfactorily under abnormal voltage.  Electric power saving.  Operating temperature is less.  Noise level is lower.
12. Disadvantages Portability. Initial cost is more. Speed Control . Applications Motors are suitable for wide industrial applications like paper, cement, textiles, cranes, material handling, machine tools and blowers etc.
13. CONCLUSION:Finally i conclude that most of the industrial loadshaving motors are consuming 70% of the totalelectricity.so it is better to replace standard motorswith energy efficient motors where evereconomical. so thatwe can Save energy. Save money. Save atmosphere from pollution.
14. REFERENCES: Wikipedia.com Slide share.com Project form.com Student seminar.com
15. Thank you

Energy Efficient Motors
Description
Energy efficient motors use less electricity, run cooler, and often last longer than NEMA (National Electrical Manufacturers Association) B motors of the same size.

To effectively evaluate the benefits of high efficiency electric motors, we must define "efficiency". For an electric motor, efficiency is the ratio of mechanical power delivered by the motor (output) to the electrical power supplied to the motor (input).

Efficiency = (Mechanical Power Output / Electrical Power Input) x 100%

Thus, a motor that is 85 percent efficient converts 85 percent of the electrical energy input into mechanical energy. The remaining 15 percent of the electrical energy is dissipated as heat, evidenced by a rise in motor temperature. Energy efficient electric motors utilize improved motor design and high quality materials to reduce motor losses, therefore improving motor efficiency. The improved design results in less heat dissipation and reduced noise output.

Most electric motors manufactured prior to 1975 were designed and constructed to meet minimum performance levels as a trade-off for a low purchase price. Efficiency was maintained only at levels high enough to meet the temperature rise restrictions of the particular motor. In 1977, the (NEMA) recommended a procedure for labeling standard three-phase motors with an average nominal efficiency. These efficiencies represent an industry average for a large number of motors of the same design. Table 1 compares the current Standard full load nominal efficiencies for standard and energy efficient motors of various sizes. Note that these efficiencies are averages for three-phase Design B motors. (Design B motors account for 90 percent of all general purpose induction motors. See NEMA Specifications Publication MG-1-1.16 for classifications of induction motors.) Motors of other types (Design A, C, or D) have slightly different efficiencies, while single phase motors have substantially lower efficiencies. Energy efficient motors are only marketed with NEMA B speed-torque characteristics.


TABLE 1
Average Full Load Nominal Efficiencies Standard and Energy Efficient Motors
Rated hp
Standard Motor*
High-Efficiency Motor*
1.0
75.5
82.6
1.5
78.1
83.3
2.0
80.5
83.8
3.0
81.2
87.7
5.0
82.8
88.6
7.5
83.8
89.8
10.0
85.2
90.1
15.0
86.8
91.3
20.0
87.8
91.9
25.0
88.3
92.8
30.0
89.1
92.7
40.0
89.6
93.3
50.0
90.5
93.8
60.0
90.6
94.1
75.0
91.2
94.4
100.0
91.8
94.7
125.0
92.4
95.3
150.0
92.9
95.5
200.0
94.0
95.4

*Design B, Four Pole, Three-Phase
Motor efficiency is a factor of a variety of mechanical and electrical imperfections within the motor. Resistance (I2R) losses in the stator windings and rotor bars can constitute up to a 15 percent loss in efficiency in three-phase motors. I2 R losses in single phase fractional horsepower motors may be as high as 30 percent. Magnetization losses in the stator and rotor cores cause about a 1 percent to 7 percent efficiency loss. Friction losses in the bearings and inefficiency in the cooling fans result in 0.5 percent to 1.5 percent loss in motor efficiency. Friction and magnetization losses are independent of motor load and relate solely to motor size and design. The remaining losses are referred to as stray load losses. Severely underloaded motors have lower efficiencies because the friction and windage and core losses remain constant and comprise an increasingly larger percentage of total motor power consumption. The figure below shows the various components of motor losses as a function of motor load.


The construction materials and mechanical and electrical design of a motor dictate its final efficiency. Energy efficient motors utilize high quality materials and employ optimized design to achieve higher efficiencies. Large diameter copper wire in the stator and more aluminum in the rotor reduce resistance losses of the energy efficient motor. Improved rotor configuration and optimized rotor-to-stator air gap result in reduced stray load losses. An optimized cooling fan design provides ample motor cooling with a minimum of windage loss. Thinner and higher quality steel laminations in the rotor and stator core allow the energy efficient motor to operate with substantially lower magnetization losses. High quality bearings result in reduced friction losses.

Cost-Savings Analysis
When considering energy efficient motors, two factors will affect the payback period: power cost and operating hours per year. Where electricity is inexpensive or operating time is low, it may take several years for the savings from installation of high efficiency motors to outweigh the difference in initial cost. On the other hand, where power costs and the operating hours per year are high, it may be possible to replace an existing standard efficiency motor with an energy efficient motor and realize a paycheck of less than one year (Table 2). Furthermore, the economic advantages of energy efficient motors over rewound motors often provide the opportunity for an upgrade to energy efficient motors when old motors burn out.

TABLE 2
Motor Choice Decision Matrix with Example of a 10-HP
AC-Polyphase Induction Motor

Standard Motor
High Efficiency Motor

A
B
C
1. First Cost
$180
$224
$252
$279
2. %Life = Annual Cost
$22.50
$28.00
$31.50
$34.88
3. Electricity Required (kW)
8.78
8.52
8.43
8.38
4. Hours Use/Year
4,000
4,000
4,000
4,000
5. Efficiency
85.0
87.5
88.5
89.0
6. kWh/Year**
35,120
34,080
33,720
32,520
7. Cost/kWh (Energy + Demand)
$0.06
$0.06
$0.06
$0.06
8. Annual Electric Cost
$2,107
$2,045
$2,023
$2,011
9. Difference in Electricity Costs
-0-
$62.00
$84.00
$96.00
10. Total Annual Cost
$2,130
$2,073
$3,055
$2,046
11. Payback - Years***
-0-
0.71
0.86
1.03
Source: NEMA Publication MG-1.
Factors to Remember When Buying Energy Efficient Motors:
Not all high efficiency motors are created equal. NEMA requires that the average nominal efficiency test method be listed on the nameplate. IEWC 34-2 and JEC 37 test methods result in slightly higher efficiencies than the IEEE 112 method. Current NEMA codes require that the motor nameplate carry both the efficiency and test standards.
Motors perform best at full load. An underloaded motor, energy efficient or not, is less efficient than a fully loaded motor.
Energy efficient motors are most attractive economically when power costs and/or operating hours per year are high.


Until recently,

there was no single definition of an energy-efficient motor. Similarly, there were no efficiency standards for standard NEMA design B polyphase induction motors. As discussed earlier, standard motors were designed with efficiencies high enough to achieve the allowable temperature rise for the rating. Therefore, for a given horsepower rating, there is a considerable variation in efficiency. This is illustrated in Fig. 2.1 for the horsepower range of 1-200 hp.
In 1974, one electric motor manufacturer examined the trend of increasing energy costs and the costs of improving electric motor efficiencies. The cost/benefit ratio at that time justified the development of a line of energy-efficient motors with losses approximately 25% lower than the average NEMA design B motors. This has resulted in a continuing industry effort to decrease the watt losses of induction motors. Figure 2.3 shows a comparison between the full-load watt losses for standard four-pole, 1800-rpm NEMA design B induction motors, the first-generation energy-efficient motors with a 25% reduction in watt losses, and the current energy efficient motors. The watt loss reduction for the current energy-efficient four-pole, 1800-rpm motors ranges from 25 to 43%, with
Full-load losses, standard NEMA Design B 1800-rpm motors versus first-generation energy-efficient motors (25% loss reduction) and current energy-efficient motors.
FIGURE 2.3 Full-load losses, standard NEMA Design B 1800-rpm motors versus first-generation energy-efficient motors (25% loss reduction) and current energy-efficient motors.
an average watt loss reduction of 35%. Figures 2.4a and 2.4b illustrate the nominal efficiencies of the current energy-efficient (E.E.) motors, the first-generation energy-efficient motors (25% loss reduction), and current standard NEMA design B four-pole, 1800-rpm motors.
Subsequent to the development of this first line of energy-efficient motors, all major electric motor manufacturers have followed suit. Since, as previously discussed, there was no standard for the efficiency of motors, the energy-efficient motors of the various manufacturers can generally be identified by their trade names. In addition, these
a) Nominal full-load efficiency comparison 1800-rpm open induction motors. (b) Nominal full-load efficiency comparison 1800-rpm TEFC induction motors.
FIGURE 2.4 (a) Nominal full-load efficiency comparison 1800-rpm open induction motors. (b) Nominal full-load efficiency comparison 1800-rpm TEFC induction motors.
products are supported by appropriate published data. Following are examples of these trade names and their manufacturers:


E-Plus®, E + in® Magnet ek
Energy Saver™ General Electric
XE Energy Efficient Reliance Electric Co.
Super E Baldor Electric Co.
Spartan High Efficiency Magnetek/Tjouis Allis
Corro-Duty Premium Efficiency U.S. Electrical Motors
Premium Efficiency Division of Emerson Electric
Co. Seimens
Premium Efficiency Toshiba/Houston Intl.
A survey of the published data available from the manufacturers of energy-efficient motors is summarized in Table 2.4 and Fig. 2.5. These data show the nominal average efficiency as well as the range of nominal efficiencies expected. The efficiencies are shown as nominal efficiencies as defined in NEMA Standards Publication MG1. When these efficiency data are compared to the standard motor efficiency data shown in Fig. 2.1, the range in efficiency for a given horsepower is considerably less; in other words, energy-efficient motors tend to be more uniform than standard motors.
When the average nominal efficiency for industry energy-efficient motors shown in Tables 2.4a and 2.4b is compared to the data shown in Fig. 2.4 for standard motors, the industry average is consistently higher. When the average efficiency for standard motors in Fig. 2.1 is compared to the average efficiency for current energy-efficient motors in Figs. 2.5a and 2.5b the average loss reduction is 35%, thus indicating a continuing trend to higher-efficiency motors. These improvements in efficiency, or loss reductions, are generally achieved by increasing the amount of active material used in the motors and by the use of lower-loss magnetic steel. Figure 2.6 shows this comparison of a standard motor and an energy-efficient motor for a particular horsepower rating. In addition to increasing the motor efficiency, there are other user benefits in the application of energy-efficient motors, which will be discussed in more detail in

TABLE 2.4a Full-Load Nominal Efficiencies of Three-Phase Four-Pole Energy-Efficient Open Motors”

Full-Load Nominal Efficiencies of Three-Phase Four-Pole Energy-Efficient Open Motors"
topic 5. This trend will probably continue as the cost of power and the demand for higher-efficiency motors continue to increase. Figure 2.7 shows the trend in the loss reduction and efficiency improvement of a 50-hp polyphase induction motor. Other induction motors from 1 to over 200 hp have followed a similar trend.

Choice/replacement of the motor

Those wishing to improve passive energy efficiency often consider replacing motors as a starting point, especially if the existing motors are old and require rewinding.

This trend is reinforced by the determination of major countries to stop low-efficiency motor sales in the near future. Based on the IEC60034-30 Standard’s definition of three efficiency classes (IE1, IE2,IE3), many countries have defined a plan to gradually force IE1 and IE2 motor sales to meet IE3 requirements.

In the EU, for example, motors of less than 375 kW have to be IE3-compliant by January 2015 (EC 640/2009).

There are two reasons for replacing an old motor:

To benefit from the advantages offered by new high-performance motors (see Fig. K13)

Fig K08 2013.jpg

Fig. K13: Definition of energy efficiency classes for LV motors, according to Standard IEC60034-30


Depending on their rated power, high-performance motors can improve operational efficiency by up to 10% compared to standard motors. By comparison, motors which have undergone rewinding see their efficiency reduced by 3% to 4% compared to the original motor.

To avoid oversizing
In the past, designers tended to install oversized motors in order to provide an adequate safety margin and eliminate the risk of failure, even in conditions which were highly unlikely to occur. Studies show that at least one-third of motors are clearly oversized and operate at below 50% of their nominal load.

However:
- Oversized motors are more expensive.
- Oversized motors are sometimes less efficient than correctly sized motors: motors are at their most effective working point when operating between 30% and 100% of rated load and are built to sustain short periods at 120% of their rated load.

Efficiency declines rapidly when loads are below 30%.
- The power factor drops drastically when the motor does not work at full load, which can lead to charges being levied for reactive power.

Knowing that energy costs account for over 97% of the lifecycle costs of a motor, investing in a more expensive but more efficient motor can quickly be very profitable.

However, before deciding whether to replace a motor, it is essential:

to take the motor’s remaining life cycle into consideration.
to remember that the expense of replacing a motor even if it is clearly oversized, may not be justified if its load is very small or if it is only used infrequently (e.g. less than 800 hours per year see Fig. K14).
to ensure that the new motor’s critical performance characteristics (such as speed)are equivalent to those of the existing motor.

Fig K09 2013.jpg

Fig. K14: Life cycle cost reduction for IE2 and IE3 motors compared to IE1 motors, depending on the number of operating hours per year


Operation of the motor

Savings can be made by:

Replacing an oversized old motor with an appropriate high-efficiency motor
Operating the motor cleverly
Choosing an appropriate motor starter/controller
Other approaches are also possible to improve the energy efficiency of motors:

Improving active energy efficiency by simply stopping motors when they no longer need to be running. This method may require improvements to be made in terms of automation, training or monitoring, and operator incentives may have to be offered. If an operator is not accountable for energy consumption, he/she may well forget to stop a motor at times when it is not required.
Monitoring and correcting all the components in drive chains, starting with those on the larger motors, which may affect the overall efficiency. This may involve, for example, aligning shafts or couplings as required. An angular offset of 0.6 mm in a coupling can result in a power loss of as much as 8%.

Control of the motor

The method for starting/controlling a motor should always be based on a system-level analysis, considering several factors such as variable speed requirements, overall efficiency and cost, mechanical constraints, reliability, etc.

To ensure the best overall energy efficiency, the motor’s control system must be chosen carefully, depending on the motor’s application:

For a constant speed application, motor starters provide cheap, low-energyconsumption solutions. Three kinds of starters can be used, depending on the system’s constraints:
Direct on line starter (contactor)
Star Delta starter: to limit the inrush current, provided that the load allows a starting torque of 1/3 of nominal torque
Soft starter: when Star Delta starter is not suitable to perform a limited inrush current function and if soft braking is needed.
Example of constant speed applications: ventilation, water storage pumps, waste water treatment stirring units, conveyors, etc.

PB116781.jpg PB116782.jpg PB116783.jpg
LC1 D65A•• LC3 D32A•• ATS48••
Fig. K15: Motor starter examples: TeSys D Direct on line contactors, Star Delta starter, Altistart softstarter (Schneider Electric)


When the application requires varying the speed, a Variable Speed Drive (VSD) provides a very efficient active solution as it adapts the speed of the motor to limit energy consumption.
It competes favourably with conventional mechanical solutions (valves, dampers and throttles, etc.), used especially in pumps and fans, where their operating principle causes energy to be lost by blocking ducts while motors are operating at full speed.

VSDs also offer improved control as well as reduced noise, transient effects and vibration. Further advantages can be obtained by using these VSDs in conjunction with control devices tailored to meet individual requirements.

As VSDs are costly devices which generate additional energy losses and can be a source of electrical disturbances, their usage should be limited to applications that intrinsically require variable speed or fine control functions.

Example of variable speed applications: hoisting, positioning in machine tools, closed-loop control, centrifugal pumping or ventilation (without throttle) or booster pumps, etc.

PB116784.jpg PB116785.jpg PB116786.jpg
Altivar 12 (≤ 4 kW ) Altivar 212 (≤ 75 kW) Altivar 71 (≤ 630 kW)
Fig. K16: Variable Speed Drives of various power ratings (Altivar range, Schneider Electric)

To handle loads that change depending on application requirements, starters, VSDs, or a combination of both with an appropriate control strategy (see cascading pumps example Fig. K17) should be considered, in order to provide the most efficient and profitable overall solution.
Example of applications: HVAC for buildings, goods transport, water supply systems, etc.

The method for starting/controlling a motor should always be based on a systemlevel analysis, considering several factors such as variable speed requirements, overall efficiency and cost, mechanical constraints, reliability, etc.


None

Fig. K17 : Example of cascading pumps, which skilfully combine starters and a variable speed drive to offer a flexible but not too expensive solution