Design and Technologies for Energy Efficient Motors

AEEE , Pune 5th Aug. 2011

A.V.Bhalerao, Chief Technology Officer – Motors & Drives

Why have high efficiency motors

Save energy – this is a national priority

Reduce operating cost

Reduce harmful greenhouse gas emissions

Energy Efficient Motors A National Priority

70 % of all electrical energy consumed in India is used for driving electric motors

55 % of which is consumed by industrial motors

Consumption of Electricity by Sector

INDUSTRY; 39%

AGRICULTURE, 31%

OTHERS; 30%

A saving of 1 or 2 % by industry can save 500 MW

Initial Cost of an 11 kW motor is only 3.9% in the first year of operation

Purchase Cost (Rs), 24862/-, 3.9%

Annual Energy Cost (Rs) 6,42,700/-, 96.1%

Assumptions: Efficiency Eff2 : 89.0% (BBL)

Energy cost: Rs 6.5 per kWH

Working: 8000 hrs pa

Life Cycle Cost of a Motor

In one year, a motor consumes energy equivalent to 10 to 25 times its purchase price

Many consumers in India especially OEMs purchase cheap motors having low efficiency values

National Standard for Energy Efficient Motors

IS 12615: 2004 (First Revision)

Energy Efficient Induction Motors — Three Phase Squirrel Cage

IS 12615 covers Energy Efficient motors from 0.37kW to 160kW (up to Fr. 315L)

IS 12615 specifies two efficiency levels : - eff2 and eff1

IS 12615: 2004 (Second Revision) ( Under printing now)The new revision is in line with IEC 60034-30 ““Efficiency classes of single speed 3 phase cage induction motors” .

Defines efficiency classes IE1, IE2 and IE3.

Range covered now upto 375 kW

Testing as per IEC 60034-2-1

IE1 and IE2 : Slightly lower than eff2 and eff1 (to compensate for new testing method in which stray losses are higher)

Comparison of eff & IE classes

Output eff2 IE1 eff1 IE2 IE3 IE4

5.5kW 4P 85.7 84.7 89.2 88.2 89.9 91.3

11kW 4P

88.4 87.6 91.0 90.2 91.7 92.9

IS 12615: 2004 (First revision) - superior to existing Std. IS 8789 To be considered as energy efficient, a motor must conform to one of the following

efficiency levels specified in IS 12615:

Improved Efficiency (eff2)

High Efficiency (eff1)

eff1 efficiency levels are higher than those of eff2

Both eff1 & eff2 are higher than the nominal values specified in IS 8789: 1996

Why does revised IS 12615 specify three efficiency levels? User has the option to go for IE2 or IE3 motor and save energy but at higher initial

cost. It is strongly recommended to go for IE2 motor when utilization is high

The standard is hence user friendly since it has provided three levels of efficiency.

This in line with other international standards like IEC.

Comparison of efficiencies of Standard & Energy Efficient Motors

Output 4 Pole IS 8789eff2 as per

IS 12615

eff1 as per

IS 12615

0.75 kW 71.0% 73.0% 82.5%

1.5 kW 76.0% 78.5% 85.0%

3.7 kW 83.0% 84.0% 88.3%

11 kW 85.5% 88.4% 91.0%

18.5kW 87.0% 90.0% 92.2%

37 kW 88.5% 92.0% 93.6%

75 kW Not specified 93.6% 94.7%

110 kW Not specified 94.4% 95.2%

160 kW Not specified 95.0% 95.8%

Efficiency values are subject to tolerance as per IS325

Why is the Energy Efficient motor more expensive?

eff1 motors are generally priced 5 - 15 % higher than eff2 motors

More laminations - longer core length and/or

High Grade (low loss) laminations

More Copper

Rs

How is efficiency improved? Increase in Active material

Reduce Stator Cu Loss

Reduce Rotor Cu Loss

Reduce Iron Loss Reduce Copper Loss

Low Loss Magnetic matl.

ReduceFlux Density

Increased Starting current Speed

IncreaseCopper SectionStator slot area

IncreaseRotor bar section

Reduced Starting Torque

Increase ReduceStator Yoke Rotor Dia

Core length has to be increased to maintain starting torque

How is efficiency improved?

Cooling fan size:

Since losses are reduced in an EE motor, it requires less cooling air. Hence fan size can be reduced, resulting in reduction of fan losses.

Special low loss bearings:

SKF have developed a new range of Energy Efficient (E2) bearings for energy savings. These can be used to reduce friction losses. ( Reduction of upto 30 % possible)

Energy Efficient Motors have a Flat Efficiency Vs Load Characteristic

60

70

86

89 89

80

8485.5

60

65

70

75

80

85

90

95

25% 50% 75% 100%

Load

Eff

icie

nc

y

Motor As per IS 8789 eff2 Motor

Motor rating is selected for max. load conditions and next preferred rating

Most motors operate on an average around 75% load

Efficiency is almost same from 60% to 100% load in a well designed EE motor

eff2 motor gives savings over an IS 8789 motor

Pay Back Period of eff2 motor is 0.7 month for a 10% price increase over an IS 8789 motor

  IS 8789 eff2

Purchase Price of 11kW/4P motor Rs 22600 24862

Efficiency 85.5% 89.0%

Energy consumption p.a. for 8000 Hrs @ Rs 6.5 per kWh

6,69,000 6,42,700

Energy Saving p.a. Rs 26,300

Additional purchase price Rs 2262

eff1 motor gives further savings over an eff2 motor

  eff2 eff1

Purchase Price of 11kW/4P motor Rs 24862 28590

Efficiency 89.0% 91.5%

Energy consumption p.a. for 8000 Hrs @ Rs 6.5 per kWh

6,42,700 6,25,140

Energy Saving Rs 17563

Additional purchase price Rs 3728

Pay Back Period of eff1 motor is 2.5 months for a 15% price increase over eff2 motor

Energy savings at partial loads

11kW-4 Pole BBL eff2 motor Vs eff1 motor.

Total Energy saving per annum : Rs 14230

Additional Price of eff1 motor over eff2 motor : Rs 3728

Payback Period is 3.1 Months

Load 100% 75% 50%

Working Hrs. p.a. 3000 3000 2000

Eff of eff1 (BBL stock motor) 91.5% 91.5% 89.5%

Eff of eff2 (BBL stock motor) 89% 89% 86%

Difference in input power (kW) 0.338 0.338 0.50

Energy saving p a @ Rs 6.5 per kWh Rs. 6585 Rs 4394 Rs. 3251

Difference in input power (kW)

Energy Savings Ready Reckoner

Energy Savings Ready Reckoner for eff1 MotorsYou must enter blue cells                        

Motor Rating / Polarity 45 kW / 4P   225M eff2 

Energy Cost: Rs / kWH 5   225M eff1 

% of load 0% load 50% load

75% load

100% load Total Purchase Price of

Motor in Rs Working Hrs pa.   2000 3000 3000 8000  

Efficiency of eff1   91.9 93.9 93.9   83149

Efficiency of eff2   91 93.2 93.2   75592

eff2 motor: kWH pa. 0 49451 108637 144850 302938  

eff1 motor: kWH pa. 0 48966 107827 143770 300564  Energy Saving: Rs.

pa. 0 2421 4049 5399 11870 7557

                                        Pay Back Period 7.6 months       

Energy Efficient Motors- Speed and Starting current

Due to reduced rotor losses, speed is higher.(5-15rpm)

The driven equipment ( fan / pump ) should be designed accordingly

Due to reduced rotor and stator resistance, starting current is higher. This can go to 700 % in eff1 motors.

When used with a VVVF drive, this does not matter as the drive takes care. In other cases, this should be taken care during system design.

Bharat Bijlee Range of eff1 & eff2 motors.

eff2 and eff1 motors are offered by Bharat Bijlee ex-stock

Bharat Bijlee also offers a complete range of eff1 customised motors orders with a

lead time of 8 weeks

Bharat Bijlee does not manufacture motors of efficiency class less than eff2

Energy Efficient Motors for Hazardous Areas

BBL has standard catalogued energy efficient series motors for use in hazardous areas

Type MD – Flameproof Ex(d) eff2 Type MJ – Flameproof Ex(d) eff1 Type ME – Increased Safety Ex(e) eff2 Type MI – Increased Safety Ex(e) eff1 Type MN – Non Sparking Ex(n) eff2 Type MS – Non Sparking Ex(n) eff1

Energy Efficient Motors- Flameproof, Increased Safety &

Non sparking motors

eff1 motors can also be offered against customer requirement with a lead time of 8 to 10 weeks

In a few eff1 outputs, next higher frame size is required

Nameplates - marking of Efficiency

Bharat Bijlee EE motors are clearly labeled “Eff 1 or Eff2”

BB High Efficiency Motor

When Should I Consider an eff1 motor

More than 4000 hours of operation per annum

New installations, typically HVAC systems and process industries

Replace with eff1 instead of rewinding old motors

- rewinding increases iron and stray losses

As part of a preventive maintenance or energy conservation plan

Intermittent duty applications….?

Intermittent duty motors are typically used in crane, hoist, valve actuators and other

applications with frequent starts

In these applications, motors are designed for low starting losses rather than low

running losses

For intermittent duty applications EE motors are not the best choice

Problems in field testing

Efficiency measurement at site is unreliable.

One needs to decouple the load in order to measure no load losses

Variable voltage supply required in order to maintain rated voltage

We recommend measurement of kWh using a energy meter and compare two motors

Measurement of current is not a reliable indicator. Current is not directly proportional

to input power because power factor varies with load and voltage

Successful case studies

Industry : Textiles : Applications : Yarn Twisters, Spinning frame

Existing mills in Surat had,

1) Existing old motors, rewound several times

2) Low load factors

3) Long hours if operation

Approach : 1) Extensive seminars, both in house and in common forums

2) Discussions with users at several levels and working out of potential

payback and power savings

3) Sample trials and actual demonstration of energy savings.

4) Payback 6 to 12 months for new motors

5) Client placed orders for about 200 eff1 motors and installed.

6) Other mills in same area are changing over to eff1.

Successful case studies

Industry : Paper : Century Pulp and Paper, Venkraft Papers

: HVAC : Blue Star, Voltas

: Fertilizer : Deepak Fertilizers : Hazardous area Ex(d) and Ex(e) eff1

motors

: Pharmaceuticals : Jubilant Organosys :( Ex(d) and Ex(e) eff1 motors)

: Chemical : Grasim Industries

Approach: 1) Extensive seminars, both in house and in common forums

2) Seminars and discussions with consultants. Showing how eff1 can be

achieved even in hazardous area motors.

3) Jointly working out of correct power ratings of various applications.

4) Calculations of power savings .

5) Clients witnessing actual type tests at our works and seeing the

efficiencies being achieved.

6) Customer support whenever required.

Testimonial from Grasim Industries – Chemical Division

TO WHOMSOEVER IT MAY CONCERN

We are using Bharat Bijlee make energy efficient motors ranging from 5HP

to 100 HP since last 2 years and their performance is satisfactory. We have

achieved substantial savings by way of energy conservation.

For GRASIM CHEMICAL DIVISION

KBV PRASANNARAO

GENERAL MANAGER (ELECT. & INST)

Selective list of our eff1 Customers

Abhishek Industries A.P.Solvex Ltd B.A.R.C. DSM Anti-Infective (I) Ltd. Finolex Industries Garden Silk Mills Grasim Industries G.V.D. Textiles Hindustan Zinc Hightemp Furnace Ltd. Indian Steel Co Ltd. JCB (I) Ltd Koramandala Fertilizers KSB Pumps

TEFC Motors: VVF Rathi Group Sandoz Ultratech Cement Ltd. Power Build Ltd. IFFCO Century Rayon Thermax Ltd. Mather and Platt Kanoria Chemicals Essar Steel Gujarat Narmada Valley GSFC Nirma Ltd. Taj Group of Hotels

Purvi Pumps Aditya BIirla Nuvo Ltd. Savita Chemicals Ltd. Kilburn Engg. Ltd. Sutlej Textiles Metso Minerals (India) Yuken India Ltd. ELGI Equipments Ltd. Divi’s Laboratories Ltd New Allenbury Works Varat Pumps & M/cs Shanti Gears Ltd. Rank Cranes Pashupati Spinning Kirloskar Ebara

Selective list of our eff1 Customers

DCW Ltd.

Divis Lab.

DSM Anti-Infective (I) Ltd.

Ingersoll Rand (I) Ltd.

Ranbaxy Industries.

Aarti Industries

Hikal Ltd

GMM Pfaudler Ltd.

Hazardous Area Motors (Flameproof and Increased safety) :

Kilburn Engg. Ltd.

Themax Ltd.

VVF Ltd

Sandoz Pvt.Ltd.

Kanoria Chemicals & Industries

Dresser-Rand India Pvt Ltd.

Gujarat Narmada Valley

KSB Pumps

Milton Roy India

Growth in Eff1 motors business

  % Eff1 to stdYear kW Value

2007 - 08 4.6 4.32008 - 09 14 12.52009 -10 21 182010 -11 25.3 21

Bharat Bijlee manufactures the complete range of Energy Efficient motors

conforming to eff1 of IS 12615. These are all catalogued ratings.

Bharat Bijlee maintains stocks of popular ratings of eff1 motors

Customer awareness and interest.

Summary and Conclusions

There exists a national standard IS 12615: 2004

(Revision 1) for energy efficient three phase induction motors from 0.37kW to 160 kW.

(Revision 2) will bring it in line with IEC stds and extends range to 375 kW

Energy savings are more at partial loads because Energy Efficient motors have a

Flat Efficiency Vs. Load Characteristic

Payback period of eff2 motor over IS-8789 motor is approx 1500 working hrs.

Payback period of eff1 motor over eff2 motor is approx 2500 working hrs.

Customers realize that they actually save huge amount in power bills.

Successful introduction initially requires close interaction with customer.

Use of Energy efficient motors is on the rise.

Thank You