Bharat Bijlee Bhalerao

Report
Design and Technologies for Energy Efficient
Motors
A.V.Bhalerao, Chief Technology Officer – Motors & Drives
AEEE , Pune 5th Aug. 2011
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
OTHERS, 30%
INDUSTRY, 39%
AGRICULTURE,
31%
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
88.4
87.6
91.0
90.2
91.7
92.9
11kW
4P
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 8789
eff2 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 Copper Loss
Reduce Iron Loss
Reduce
Stator Cu Loss
Reduce
Flux Density
Low Loss Magnetic
matl.
Increase
Stator Yoke
Increase
Copper Section
Stator slot area
Reduce
Rotor Dia
Reduce
Rotor Cu Loss
Increase
Rotor bar section
Increased
Starting current Speed
Reduced Starting Torque
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

95
Motor rating is selected for max. load
conditions and next preferred rating
Most motors operate on an average
around 75% load
89
89
90
86
85
Efficiency

85.5
84
80
80
75
70
70
65
60
60
25%
Efficiency is almost same from
60% to 100% load in a well
designed EE motor
75%
50%
100%
Load
Motor As per IS 8789
eff2 Motor
eff2 motor gives savings over an IS 8789 motor
IS 8789
eff2
Purchase Price of 11kW/4P motor Rs
22600
24862
Efficiency
85.5%
89.0%
6,69,000
6,42,700
Energy consumption p.a. for 8000 Hrs @ Rs
6.5 per kWh
Energy Saving p.a. Rs
Additional purchase price Rs
26,300
2262
Pay Back Period of eff2 motor is 0.7 month for a 10% price increase over an IS 8789 motor
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%
6,42,700
6,25,140
Energy consumption p.a. for 8000 Hrs @ Rs
6.5 per kWh
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.
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
Rs. 6585
Rs 4394
Rs. 3251
Energy saving p a @ Rs 6.5 per kWh
Total Energy saving per annum : Rs 14230
Additional Price of eff1 motor over eff2 motor : Rs 3728
Payback Period is 3.1 Months
Energy Savings Ready Reckoner
Energy Savings Ready Reckoner for eff1 Motors
You must enter blue cells
Motor Rating / Polarity
45 kW / 4P
Energy Cost: Rs / kWH
5
225M
eff2
225M
eff1
Total
Purchase Price of
Motor in Rs
Working Hrs pa.
50%
load
2000
75%
load
3000
100%
load
3000
Efficiency of eff1
91.9
93.9
93.9
83149
Efficiency of eff2
91
93.2
93.2
75592
% of load
0% load
8000
eff2 motor: kWH pa.
0
49451 108637 144850
302938
eff1 motor: kWH pa.
Energy Saving: Rs.
pa.
0
48966 107827 143770
300564
0
2421
Pay Back Period
4049
7.6
5399
11870
months
7557
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

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Type MD
Type MJ
Type ME
Type MI
Type MN
Type MS
– Flameproof Ex(d) eff2
– Flameproof Ex(d) eff1
– Increased Safety Ex(e) eff2
– Increased Safety Ex(e) eff1
– Non Sparking Ex(n) eff2
– 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
BB High Efficiency Motor
Bharat Bijlee EE motors are clearly labeled “Eff 1 or Eff2”
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
TEFC Motors:
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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
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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
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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
Hazardous Area Motors (Flameproof and Increased safety) :
 DCW Ltd.
 Divis Lab.
 DSM Anti-Infective (I) Ltd.
 Ingersoll Rand (I) Ltd.
 Ranbaxy Industries.
 Aarti Industries
 Hikal Ltd
 GMM Pfaudler Ltd.
 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
Year
2007 - 08
2008 - 09
2009 -10
2010 -11
% Eff1 to std
kW
Value
4.6
4.3
14
12.5
21
18
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

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