INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

Beyond Induction Motors LOT-30 New EU Ecodesign Study

Anibal T. De Almeida UNIVERSITY OF COIMBRA Portugal 1/46

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

LOT-30 Product Definition • Lot 30: Products outside the scope of Regulation 640/2009 on electric motors, such as: – On-line AC Motors, including Permanent Magnet motors, from 120W-1000kW – Variable Speed Motors, from 120W-1000kW – drives, such as soft starters, torque or variable speed drives (VSD) from 200W–1 000kW.

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ISR – University of Coimbra 2

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

Categorisation For the purpose of this study, motors shall be divided into three major categories according to output power: 1. Small Motors – 120 W to 750 W 2. Medium Motors – 0,75 kW to 375 kW 3. Large Motors – 375 kW to 1000 kW – Low Voltage and Medium Voltage (6600 kVA)

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ISR – University of Coimbra 3

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

Focus on System approach

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ISR – University of Coimbra 4

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

Motor Controllers • The high potential savings of Variable Speed control, especially in centrifugal load applications, is also widely recognized and is to be the subject of further analysis including hardware, software and interaction with the motor, to evaluate its combined efficiency. • Other motor controllers, which can be applied in loads with small variability, such as SoftStarters. 5/46

ISR – University of Coimbra 5

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

Typical full-load efficiency levels for VSDs

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

IE2

IE4 ↑

EPAct

IE3 IE3 Premium

PM MOTOR

Standard

IE4

WITH CAGE (LINE-START)

IE4

WITH VSD

SynR MOTOR

INDUCTION MOTOR

IE1

MOTOR TECHNOLOGY CHANGE

IEC-NEMA COMMERCIAL MOTOR TECHNOLOGY CLASSES

IE3/4 WITH VSD

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

EFFICIENCY LIMITS FOR INDUCTION MOTORS

Losses variation between IE3-class efficiency levels and commercially available “ultra” efficient 4-pole, 60-Hz IMs. 8/46

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

IE4 – Induction Motors Rated Output: 3 to 355 kW Frame sizes: EN 50347 Standard 132S to 355A/B Number of poles: 2, 4 and 6 Voltage: 400V, 50 Hz

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

What is a Super-Premium Motor ? • -Premium IE3) have 15-20% lower losses than IE2 motors • A Super-Premium (new IE4 Class) must have at least a 15% loss difference in relation to IE3 / Premium • What is the feasibility and the ambition?

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

Induction Motor Losses

Typical fraction of losses in 50-Hz, four-pole IMs 11/46

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

IE4-Super Premium Motor Promising Technologies A- Fixed Speed -Induction motors -Line-Start Permanent Magnet with Auxiliary Rotor Cage for fixed speed applications. B-Variable Speed applications Using a electronic Variable Speed Drive (VSD) -Permanent Magnet Motor -Rare Earth -Ferrite with Amorphous Metals

-Synchronous Reluctance Motors -Speed and torque control is possible

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-Large energy savings possible (e.g. variable flow pump and fan applications)

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

ENERGY-EFFICIENCY CLASSES TECHNOLOGIES Motor Technologies and their Energy-Efficiency Potential. Motor type

Linestart

IE1

IE2

IE3

Yes

Yes

Yes

Diff.

No

Yes

Yes

Yes

Yes

No

Yes

Yes

Yes

Diff.

No

Yes Yes Yes No Some Yes* (note 1) Some

Yes Yes Yes Yes Yes

Yes Dif. Yes Yes Yes

Yes No Diff. Yes Yes

Diff. No No Yes Diff.

No No No Diff. No

Yes

Yes

Yes

Yes

Diff.

Yes

Yes

Yes

Diff.

No

Random and form wound windings; IP2x (open motors) Three-phase SCIM

IP4x and above Random wound windings (enclosed motors) Form wound windings

3-phase wound-rotor induction motors 1 capacitor Single-phase SCIM 2 switchable capacitors VSD-fed PMSM Wound-rotor Synchronous motors LSPM Sinusoidal-field reluctance

IE4

IE5

Note 1: (*) LSPMs have some limitations on their line-start capabilities with respect to torque and external inertia. Note 2: The mark: - “Yes” means that the motors are considered to be state of present commercial technology and are therefore suitable for consideration in mandatory requirements in legislation (i.e., the efficiency class is achievable with present technology, although in some cases it may not be economical); - “No” means the efficiency class is not achievable with present commercial technology; - “Diff.” (= “Difficult”) means that the energy-efficiency level may be achieved with present commercial technology for some but not all power ratings and the standardized frame-size may be exceeded; - “Line-start” means the capability of the motor to start directly from the line without the need for a VSD (direct on-line (D.O.L.) starting; Design N of IEC60034-12 for single-speed SCIMs).

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

IE4 SUPER-PREMIUM LSPM MOTORS Rated efficiency levels for commercial 50-Hz, 4-pole LSPMs from 0,55 kW to 7,5 kW and IE3-, IE4- and IE5-class limits defined in the draft of the 2nd Edition of IEC60034-30 Standard.

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

IEC60034-2-1 STANDARD Efficiency and power factor for a commercial 3-kW, 4-pole LSPM.

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16/46 IEC Frame

Weight (kg)

Power Density (W/kg)

Inertia (kg.m2)

Rated Speed (r/min)

Full-load torque (N.m)

Locked Rotor to Fullload Torque Ratio

132M

0.0465

1455

49.3 2.1

IE2

SCIM

132M

72.0 0.0528

1455

49.3

IE3

SCIM

132M

78.0 1465

48.9

LSPM

132M

61.5

Price (%)

87.0 0.84 --

2.0 7.2

89.0 0.86

100%

2.5 8.5

91.5 0.85

115%

47.8 3.8 7.8

93.0 0.93

208%

Locked Rotor to Full-load Current Ratio

Full-Load Power Factor

122.0

Full-load Efficiency (%)

96.2 6.7

1500

104.2

0.0642

Motor Technology

SCIM

116.3

0.0500

IEC Class

IE1

64.5

IE4

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

ECONOMICAL ANALYSIS OF IE1, IE2, IE3 & IE4 COMMERCIAL MOTORS Main characteristics of commercial IE2-, IE3- and IE4-class 7,5-kW, 4-pole motors.

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

IMPACT OF HIGHER SPEED OF MORE EFFICIENT MOTORS Different operating points for different motor classes

Standard Motor Torque

Synchronous Motor

Centrifugal Fan

Synchronous Speed (%) 17/46

High-Efficiency Motor

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

ECONOMICAL ANALYSIS OF IE1, IE2, IE3 & IE4 MOTORS

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Full-load torque (N.m)

Operating Point Speed (%)

Operating Point Torque (%)

Operating Point Shaft Power (%)

Operating Point Efficiency = Full-load Efficiency (%)

Operating Point Input Power (%)

Energy Savings by Replacing IE2-Class Motor (%)

T=K P∝ω

Rated Speed (rpm)

Conveyors

Motor Technology

Centrif. T∝ω2 Fans and P∝ω3 Pumps

IEC Class

Torque-Speed and Shaft Power-Speed Relation

Example of Application

Estimated Shaft Power for Different Loads Driven by 7,5-kW, 4-pole Motors of IE1, IE2, IE3 and IE4 Classes.

IE1 IE2 IE3 IE4 IE1 IE2 IE3 IE4

SCIM SCIM SCIM LSPM SCIM SCIM SCIM LSPM

1455 1455 1465 1500 1455 1455 1465 1500

49.3 49.3 48.9 47.8 49.3 49.3 48.9 47.8

100.0 100.0 100.6 103.1 100.0 100.0 100.7 103.1

100.0 100.0 101.3 106.3 100.0 100.0 100.0 100.0

100.0 100.0 101.9 109.6 100.0 100.0 100.7 103.1

87.0 89.0 91.5 93.0 87.0 89.0 91.5 93.0

102.3 100.0 99.1 104.9 102.3 100.0 97.9 98.7

–2.3 0.0 +0.9 –4.9 –2.3 0.0 +2.1 +1.3

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

ECONOMICAL ANALYSIS OF IE1, IE2, IE3 & IE4 MOTORS Estimated energy savings and payback time for IE3- and IE4-class, 7,5-kW, 4-pole motors. IEC Class Motor Technology

IE1 SCIM

IE2 SCIM

IE3 SCIM

IE4 LSPM

Motor Price with 40% Discount (€)

--

328

378

683

Price Difference (€)

--

--

50

355

Motor Efficiency (%)

87.0

89.0

91.5

93.0

VSD Efficiency (%)

97.0

97.0

97.0

97.0

VSD+Motor System Efficiency (%) 84.4 86.3 88.8 90.2 Operating Point 102.3 100.0 97.2 95.7 Input Active Power (%) Energy Savings by Replacing IE2–2.3 0.0 +2.8 +4.3 Class Motor (%) Consumption by Replacing IE2-Class 51983 50815 49426 48629 Motor (kWh/year) Energy Savings by Replacing IE2–1168 0 1388 2186 Class Motor (kWh/year) Energy Savings by Replacing IE2–81.8 -97.2 153.0 Class Motor (€/year) 0.5 2.3 Simple Payback Time (year) --Assumptions: 7511.7 W of shaft output power (1455 r/min, 49.3 N.m), 5840 hours per year of Materials usage (kg per kw) in different motor technologies operation and an electricity price of 0.07 €/kWh.

(Source: European motor manufacturer)

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

FIELD EXPERIENCE WITH IE4-CLASS 5.5-kW, 4-Pole LSPM As an example of retrofitting, an IE0-Class Equivalent, 5.5-kW, 4-pole, SCIM driving a fan in an industrial facility, has been replaced by an IE4-Class LSPM. The results are presented in next Table.

(a) IE0 SCIM

(b) IE4 LSPMSM

Photos of the replaced and replacing motors: (a) Brand A, 132S, IP55, Cl. F, 5.5 kW, 380-420V, 11.5 A, 1450 r/min, PF=0.83, Eff.=83.2% (IE0/EFF3 Class); (b) Brand B, 132S, IP55, Cl. F, 5.5 kW, 380-420V, 9.34 A, 1500 r/min, PF=0.93, Eff.=92.5% (IE4 Class).

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

FIELD EXPERIENCE WITH IE4-CLASS 5.5-kW, 4-Pole LSPM Summary of the Motor Performance for the SCIM and LSPM. Before Replacement

After Replacement

Motor Type Efficiency Class Rated Efficiency Rated Power Rated Voltage Rated Current Rated Power Factor Rated Speed Actual Voltage Actual Current Actual Power Factor Actual Input Real Power

SCIM IE0/EFF3 83.2% 5.5 kW 400 V, 50 Hz 11.5 A 0.83 1450 r/min ≈ 400 V ≈ 7,5 A 0,75 3750 W

LSPM IE4 92.5% 5.5 kW 400 V, 50 Hz 9.34 A 0.93 1500 r/min ≈ 400 V ≈ 5,5 A 0,90 3500 W

Actual Input App. Power Actual Speed Estimated Load

5100 VA 1472 r/min < 57%

4000 VA 1500 r/min < 59%

The original motor was oversized (load lower than 57%) and, therefore, a 4-kW LSPM would be enough for this application, but the user decided to maintain the rated power. Moreover, since the new 5.5-kW LSPM has a load lower than 60%, it can benefit in terms of efficiency and power factor from voltage regulation. 21/46

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

TESTS OF IE2, IE3 & IE4 MOTORS (7.5 kW, 4 Poles, 50 Hz)

-

Method 1: Harmonic Losses = Total Losses - Fundamental Losses;

Method 2: Harmonic Losses = Grid-fed Motor Losses - VSD-fed Motor Losses); (bottom) harmonic losses at full load calculated according to Method 1. - VSD supply tests, according to the IEC60034-2-3 Standard test conditions (2-level VSI, 4-kHz switching frequency).

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

TESTS OF IE2, IE3 & IE4 MOTORS (7.5 kW, 4 Poles, 50 Hz) Drive-end winding coil heads temperature rise evolution for IE2, IE3 and IE4 motors at full load, at 400 V, 50 Hz.

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

TESTS OF IE2, IE3 & IE4 MOTORS (7.5 kW, 4 Poles, 50 Hz) Experimental input current a function of load.

Nameplate Rated Values: IE2: 14.1/8.17 A | 1455 r/min IE3: 13.9/8.06 A | 1465 r/min IE4: 12.5/7.25 A | 1500 r/min

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

TESTS OF IE4 MOTOR (3 kW, 4 Poles, 400 V, 50 Hz) Efficiency as a function of load for different voltage levels, for a commercial 3-kW, 4-pole LSPM.

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

SYNCHRONOUS RELUCTANCE MOTORS Promising Technology for IE4 Class New synchronous reluctance motor (SynRM) and drive packages optimized for pump and fan applications. The new rotor has neither magnets nor windings, and thus suffers virtually no power losses – which makes it uniquely cool. A standard IM fitted with a new rotor, combined with a standard drive with new software, results in a high output, high efficiency VSD system.

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SYNCHRONOUS RELUCTANCE MOTORS Potential efficiency increase due to rotor loss reduction

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

SYNCHRONOUS RELUCTANCE MOTORS Promising Technology for IE4 Class

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IE4 COMMERCIAL MOTORS + VSD EFFICIENCY

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INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

Hitachi Super Premium Motor

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Ferrite Magnets – As alternative to Rare-Earth

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Amorphous Metal Ribbon Casting

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Magnetic Properties-AM Vs Si Steel

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Full Load Efficiency

Super-Premium Motor Efficiency

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Power

11 kW

WEG LSPM Motor (Estimated)

93.4%

ABB Synchronous Reluctance (Estimated)

93,5%

Hitachi AM PM Motor

93%

IM IE4 (limit IEC 60034-30)

93,3%

IM IE3 (limit IEC 60034-30)

91,4%

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

CONCLUSIONS Growing environmental concerns and high energy costs make more and more important to look at life-cycle costs and at non-standard technologies. PM motors prove to be significantly more efficient than SCIMs, in the low power range . Regarding single-speed applications, with direct mains operation, the SCIM still has some cost advantage, although new developments in line-start PM motors (LSPMs) make them a cost-effective alternative on a life-cycle basis. The starting torque of those motors is similar to that of SCIMs. Although the price of LSPMs is about 2 times higher than that of equivalent IE2-class motors, when considering the two options for a new application operating more than 6000 h/year, the payback time for the additional investment in the LSPMs is expected to be less than 2.5 years. 35/46

INSTITUTE OF SYSTEMS AND ROBOTICS – UNIVERSITY OF COIMBRA

CONCLUSIONS Regarding the additional harmonic losses when motors are supplied by VSDs, it was found that, at full-load, they are lower in LSPMs (in relation to those in SCIMs), thus providing additional savings in those conditions. PM motors and SynRM are additional Super Premium alternatives for variable speed applications. Finally, it should be mentioned that, in most cases, further energyefficiency optimizations will have to focus on improved system efficiency throughout the entire operating load cycle including system components, such as converter, filter, cables, motor, transmission and load/application, etc.

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