5-i 

CHAPTER 5. ENGINEERING ANALYSIS 

TABLE OF CONTENTS` 

5.1 INTRODUCTION .............................................................................................................. 1

5.2 PRODUCT CLASSES AND BASELINE MOTORS ANALYZED ................................. 2

5.2.1 Product Classes Analyzed ....................................................................................... 2

5.2.2 Baseline Models ...................................................................................................... 9

5.3 ENGINEERING ANALYSIS METHODOLOGY........................................................... 10

5.3.1 Subcontractor Software Design Approach ............................................................ 10

5.3.2 Market Motor Validation ...................................................................................... 12

5.4 COST MODEL ................................................................................................................. 13

5.4.1 Constructing a Bill of Materials ............................................................................ 14

5.4.2 Commodity Prices ................................................................................................. 15

5.4.3 Labor Costs and Assumptions ............................................................................... 17

5.4.4 Manufacturer Markups .......................................................................................... 19

5.5 RESULTS OF ENGINEERING ANALYSIS .................................................................. 19

5.5.1 Polyphase, 1 Horsepower, 4-Pole, 56-Frame Motor ............................................. 20

5.5.2 Capacitor-Start, Induction-Run, 1/2 Horsepower, 4-Pole, 48-Frame Motor ........ 22

5.5.3 Capacitor-Start, Capacitor-Run, 3/4 Horsepower, 4-Pole, 56-Frame Motor ........ 25

5.6 SCALING RELATIONSHIPS ......................................................................................... 29

5.6.1 Market Efficiency Data ......................................................................................... 29

5.6.2 Independently Tested Motor Results..................................................................... 29

5.6.3 Modeling Small Electric Motor Efficiency ........................................................... 30

5.6.4 Scaling of the Motor Losses Data ......................................................................... 31

5.6.5 CSCR Motor Scaling ............................................................................................. 32

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LIST OF TABLES 

Table 5.2.1. Representative Units Selected for the Determination Analysis .............................. 2

Table 5.2.2. Representative Units Selected for the Preliminary Analysis .................................. 3

Table 5.2.3. Representative Units Selected for the Notice of Proposed Rulemaking ................. 8

Table 5.2.4. Efficiency Ratings of Baseline Motors Selected for Analysis ................................ 9

Table 5.4.1. Labor Markups for Small Electric Motor Manufacturers ..................................... 18

Table 5.5.1. Efficiency and MSP Data for Polyphase Motor .................................................... 21

Table 5.5.2. Polyphase, 1 Horsepower, 4-Pole, 56-Frame Motor Designs ............................... 22

Table 5.5.3. Efficiency and MSP Data for Capacitor-Start, Induction-Run, 48-Frame Motor . 24

Table 5.5.4. Capacitor-Start, Induction-Run, 1/2 Horsepower, 4-Pole, 48-Frame Motor 

Designs .................................................................................................................. 25

Table 5.5.5. Efficiency and MSP Data for Capacitor-Start, Capacitor-Run Motor .................. 27

Table 5.5.6. Capacitor-Start, Capacitor-Run, 3/4 Horsepower, 4-Pole, 56-Frame Motor ........ 28

LIST OF FIGURES 

Figure 5.2.1. Polyphase Small Electric Motor Shipments Broken Down by Pole Configuration

 ............................................................................................................................... 3

Figure 5.2.2. Polyphase Small Electric Motor Shipments Broken Down by Horsepower ......... 4

Figure 5.2.3. Models of Polyphase Small Electric Motors Broken Down by Horsepower ........ 4

Figure 5.2.4. Capacitor-Start, Induction-Run Small Electric Motor Shipments Broken Down 

by Pole Configuration ........................................................................................... 5

Figure 5.2.5. Capacitor-Start, Induction-Run Small Electric Motor Shipments Broken Down 

by Horsepower ...................................................................................................... 5

Figure 5.2.6. Models of Capacitor-Start, Induction-Run Small Electric Motors Broken Down 

by Horsepower ...................................................................................................... 6

Figure 5.2.7. Capacitor-Start, Capacitor-Run Small Electric Motor Shipments Broken Down 

by Pole Configurations .......................................................................................... 7

Figure 5.2.8. Capacitor-Start, Capacitor-Run Small Electric Motor Shipments Broken Down 

by Horsepower ...................................................................................................... 7

Figure 5.2.9. Models of Capacitor-Start, Capacitor-Run Small Electric Motors Broken Down 

by Horsepower ...................................................................................................... 8

Figure 5.4.1. Standard Method of Cost Accounting for Standards Rulemaking ...................... 13

Figure 5.4.2. Five-Year Copper Wire Prices in $2008 US ....................................................... 16

Figure 5.4.3. Five-Year Die-Casting Prices in $2008 US ........................................................ 16

Figure 5.4.4. Five-Year Steel Lamination Prices in $2008 US ................................................ 17

Figure 5.5.1. Polyphase 1 Horsepower, 4-Pole, 56-Frame Motor Engineering Analysis, with 

Maximum Technology Point ............................................................................... 20

Figure 5.5.2. Polyphase 1 Horsepower, 4-Pole, 56-Frame Motor Engineering Analysis, 

without Maximum Technology Point .................................................................. 21

Figure 5.5.3. Capacitor-Start, Induction-Run, 1⁄2 Horsepower, 4-Pole, 48-Frame Engineering 

Analysis Curve, with Maximum Technology Point ............................................ 23

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Figure 5.5.4. Capacitor-Start, Induction-Run, 1⁄2 Horsepower, 4-Pole, 48-Frame Engineering 

Analysis Curve, without Maximum Technology Point ....................................... 23

Figure 5.5.5. Capacitor-Start, Capacitor-Run 3⁄4 Horsepower, 4-Pole, 56-Frame Engineering 

Analysis Curve, with Maximum Technology Point ............................................ 26

Figure 5.5.6. Capacitor-Start, Capacitor-Run 3⁄4 Horsepower, 4-Pole, 56-Frame Engineering 

Analysis Curve, without Maximum Technology Point ....................................... 26

Figure 5.6.1. Manufacturer Motor Losses for Polyphase Motors ............................................. 31

Figure 5.6.2. Manufacturer Motor Losses for CSIR Motors .................................................... 31

Figure 5.6.3. Four Pole CSIR Efficiency vs. Four Pole CSCR Efficiency ............................... 32

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LIST OF ACRONYMS AND ABBREVIATIONS 

AWG American wire gauge 

BOM Bill of materials 

CSCR Capacitor-Start, Capacitor-Run Motor 

CSIR Capacitor-Start, Induction-Run Motor 

DOE United States Department of Energy 

EISA Energy Independence and Security Act 

M* M15, M19, M56 - grade of core steel 

MSP Manufacturer Selling Price 

MPC Manufacturer Production Cost 

NEMA National Electrical Manufacturers Association 

NCI Navigant Consulting, Inc 

RPM Revolutions per minute 

TSD Technical Support Document 

SEC Securities and Exchange Commission 

U.S. United States 

μF Microfarads 

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5-1 

CHAPTER 5. ENGINEERING ANALYSIS 

5.1 INTRODUCTION 

The engineering analysis estimates the increase in manufacturer selling price (MSP) 

associated with technological and design changes that improve the efficiency of small electric 

motors. This chapter presents the U.S. Department of Energy’s (DOE’s) assumptions, 

methodology and findings for the small electric motor engineering analysis. The output from the 

engineering analysis is a “cost-efficiency” relationship for each motor analyzed which describes 

how cost changes as efficiency increases. The engineering analysis is used as an input to the lifecycle cost analysis (see Technical Support Document (TSD) chapter 8) as well as the national 

impact analysis (see TSD chapter 10). 

As discussed in chapter 3 of this TSD, the electric motors covered in this rulemaking 

include general-purpose capacitor-start, induction-run (CSIR), capacitor-start, capacitor-run 

(CSCR), and polyphase electric motors built in a National Electrical Manufacturers Association 

(NEMA) two-digit frame number series. The engineering analysis selected and analyzed one 

small electric motor from each of these three categories of covered motors. 

The engineering analysis takes input from the market and technology assessment (see 

TSD chapter 3) and the screening analysis (see TSD chapter 4). These inputs include product 

classes, baseline motor performance, methods for improving efficiency, and design options that 

have passed the screening criteria. The engineering analysis uses these inputs, coupled with 

material price estimates, design parameters, and other manufacturer inputs, to develop the 

relationship between the MSP and nominal full-load efficiency of the representative motors 

studied. For small electric motors, this relationship was evaluated using third-party design 

software, created and maintained by Yeadon Energy Systems, Inc. 

At its most basic level, the output of the engineering analysis is a curve that estimates the 

manufacturer’s selling price for a range of efficiency values. This output is subsequently markedup to determine the end-user prices based on the various distribution channels (see TSD chapter 

6). After determining customer prices by applying distribution chain markups, sales tax, and 

contractor markups, the data is combined with the energy-use and end-use load characterization 

(see TSD chapter 7) and used as a critical input to the customer’s life-cycle cost and payback 

period analysis (see TSD chapter 8). 

The results presented in this chapter do not provide a full assessment of the 

manufacturer’s costs associated with increasing efficiency levels for a small electric motor. The 

relationship presented in this chapter assumes an ideal situation, where manufacturers do not 

incur any costs associated with retooling, product redesign, training, or marketing associated 

with incorporating design changes to their product lines to achieve the efficiency levels 

presented. DOE has quantified the additional costs manufacturers would incur when complying 

with mandatory efficiency standards using the design specifications outlined in this chapter. For 

a discussion of those costs and DOE’s methodology for quantifying them, see TSD chapter 12, 

the manufacturer impact analysis. 

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In this chapter, DOE discusses the product classes analyzed and the representative motors 

selected from all covered small electric motors. DOE also presents the methodology, inputs, and 

results associated with the development of MSP versus efficiency curves for each of the 

representative motors. Finally, DOE discusses the approach used to scale the engineering 

analysis to all other product classes for the national impact analysis. 

5.2 PRODUCT CLASSES AND BASELINE MOTORS ANALYZED 

 Due to the large number of product classes, DOE did not directly analyze all covered 

motors. Instead, DOE selected representative units from the 72 product classes of small electric 

motors based on three factors: (1) the motors that were studied in the determination and 

preliminary analyses, (2) manufacturer’s sales catalogs for this equipment, and (3) the ability to 

scale from these units to other units. 

5.2.1 Product Classes Analyzed 

 In the determination analysis, DOE studied five different motors as the representative 

units. Two of the motors were capacitor-start, induction-run and three were polyphase. For the 

capacitor-start, induction-run motors, DOE chose two similar models with 56 and 48 frame 

series to capture different cost-efficiency characteristics associated with frame series. For the 

polyphase motors, DOE chose three models, holding frame series constant, but varying the 

horsepower for two motors. The five motors studied in the determination analysis are presented 

in Table 5.2.1. 

Table 5.2.1. Representative Units Selected for the Determination Analysis 

Motor Category Model Horsepower Number of Poles Frame series

CSIR Dayton 4K856 0.50 4 56

CSIR Dayton 6K965 0.50 4 48

Polyphase Dayton 3N641 0.50 4 56

Polyphase Dayton 2N103 0.50 4 56

Polyphase Dayton 3N102 1.0 4 56

In the preliminary analysis engineering analysis, DOE studied four motors: two CSIR 

motors, one CSCR motor, and one polyphase motor. The two CSIR motors analyzed had the 

same pole configuration and horsepower ratings, but were built in different frame series. The 

CSCR and polyphase motors were at incremental horsepower ratings above the two CSIR 

motors. The four motors studied in the preliminary analysis are presented in Table 5.2.2. 

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Table 5.2.2. Representative Units Selected for the Preliminary Analysis 

Motor Category Horsepower Number of Poles Frame series

CSIR 0.50 4 48

CSIR 0.50 4 56

CSCR 0.75 4 56

Polyphase 1.0 4 56

As mentioned, DOE also reviewed manufacturer catalogs. Also, DOE created a database 

of over 700 models that represent all the small electric motors manufactured and listed in the 

catalogs. Although this database does not provide information on unit sales, it does provide an 

indication of the more popular motors from the standpoint of having a greater variety of certain 

combinations of horsepower and frame series. Analyzing this data and shipments data enabled 

DOE to select popular configurations of small electric motors. 

Figure 5.2.1 through Figure 5.2.9 show shipments data for each motor category broken 

down by pole configuration and horsepower, as well as the number of models of each motor 

category broken down by horsepower 

6-Pole

7%

4-Pole

68%

2-Pole

25%

Figure 5.2.1. Polyphase Small Electric Motor Shipments Broken Down by Pole 

Configuration 

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1/4 hp

2%

1/3 hp

5%

1/2 hp

11%

3/4 hp

28%

1 hp

19%

1.5 hp

28%

2 hp

5%

3 hp

2%

Figure 5.2.2. Polyphase Small Electric Motor Shipments Broken Down by Horsepower 

Figure 5.2.1 and Figure 5.2.2 are based on projected shipments data for the National 

Impacts Analysis (see chapter 6 for more detail on the development of these data). They show 

the breakdown of shipments by pole configuration and horsepower. An overwhelming majority 

of polyphase motors shipped are four-pole machines and the weighted average horsepower of 

shipments is 1 horsepower. 

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

0.25 0.33 0.50 0.75 1.00 1.50 2.00 3.00

Number of Models

Horsepower

Figure 5.2.3. Models of Polyphase Small Electric Motors Broken Down by Horsepower 

 The data in Figure 5.2.3 are based on DOE’s database of small electric motors compiled 

from several manufacturer’s sales catalogs. This figure shows the distribution of models by 

horsepower for polyphase motors. The most common horsepower model is 1⁄2 horsepower, but 

the data show a skew toward models around 1 horsepower. This data reaffirm the weighted 

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average of 1 horsepower for polyphase motor shipments, which is why DOE selected 1 

horsepower for the polyphase representative unit. 

6-Pole

26%

4-Pole

38%

2-Pole

36%

Figure 5.2.4. Capacitor-Start, Induction-Run Small Electric Motor Shipments Broken 

Down by Pole Configuration 

1/4 hp

18%

1/3 hp

30%

1/2 hp

25%

3/4 hp

22%

1 hp

4%

1.5 hp

1%

2 hp

0%

3 hp

0%

Figure 5.2.5. Capacitor-Start, Induction-Run Small Electric Motor Shipments Broken 

Down by Horsepower 

Figure 5.2.4 and Figure 5.2.5 are based on projected shipments data for the National 

Impacts Analysis (see chapter 6 for more detail on the development of these data). They show 

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the breakdown of shipments by pole configuration and horsepower. The pole configuration 

distribution is fairly even among two, four, and six poles, but four pole motors are still the most 

common. The weighted average horsepower of CSIR motors shipped is 1⁄2 hp. 

0

2 0

4 0

6 0

8 0

100

120

140

160

0.25 0.33 0.50 0.75 1.00 1.50 2.00 3.00

Number of Models

Horsepower

Figure 5.2.6. Models of Capacitor-Start, Induction-Run Small Electric Motors Broken 

Down by Horsepower 

 The data in Figure 5.2.6 are based on DOE’s review of manufacturer catalogs and show 

the distribution of models by horsepower for CSIR motors. The most common horsepower 

model is 1⁄2 hp which reaffirms the weighted average of 1⁄2 horsepower for CSIR shipments. 

Therefore, DOE selected a rating of 1⁄2 horsepower for the CSIR representative unit. 

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6-Pole

9%

4-Pole

67%

2-Pole

24%

Figure 5.2.7. Capacitor-Start, Capacitor-Run Small Electric Motor Shipments Broken 

Down by Pole Configurations 

1/4 HP

2%

1/3 HP

6% 1/2HP

6%

3/4 HP

27%

1 HP

12%

1.5 HP

24%

2 HP

19%

3 HP

4%

Figure 5.2.8. Capacitor-Start, Capacitor-Run Small Electric Motor Shipments Broken 

Down by Horsepower 

Figure 5.2.7 and Figure 5.2.8 are based on projected shipments data for the National 

Impacts Analysis (see chapter 6 for more detail on the development of these data). These figures 

show the breakdown of shipments by pole configuration and horsepower. The pole 

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configuration distribution shows that four pole motors are the most common. The weighted 

average horsepower of CSCR motors shipped is between 1 and 11⁄2 horsepower. 

0

5

1 0

1 5

2 0

2 5

3 0

3 5

0.25 0.33 0.50 0.75 1.00 1.50 2.00 3.00

Number of Models

Horsepower

Figure 5.2.9. Models of Capacitor-Start, Capacitor-Run Small Electric Motors Broken 

Down by Horsepower 

The weighted average horsepower of CSCR motors shipped was between 1 and 11⁄2 

horsepower, but the most common horsepower model was 3⁄4 horsepower, shown in Figure 5.2.9. 

DOE did not want to choose another representative unit with a 1 horsepower rating and felt that a 

rating of 11⁄2 horsepower could overly skew the scaling results by over-representing the high end 

of the range of horsepower ratings. Therefore, DOE selected its CSCR representative unit to 

have a horsepower rating of 3⁄4, which was the same as the most common model. 

Table 5.2.3 presents the three representative units DOE selected for this NOPR analysis. 

All of the motors are four-pole motors and, in view of DOE’s analysis of manufacturer catalogs, 

this is the most common configuration for these horsepower ratings. DOE selected motors that 

approximate the middle of the range of covered horsepower ratings, partly to minimize any error 

that might be introduced as the efficiency of these motors are extrapolated to other horsepower 

ratings. 

Table 5.2.3. Representative Units Selected for the Notice of Proposed Rulemaking 

Motor Category Horsepower Number of Poles Frame series

Polyphase 1.00 4 56

CSIR 0.50 4 48

CSCR 0.75 4 56

 

 DOE identified these three as representative units of interest. All three units fit the 

requirements of a NEMA general-purpose, single speed, induction motor, rated for continuous 

duty, and built with open construction in a two-digit frame series. DOE provides additional 

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detail on each motor, including input voltage, baseline efficiency, and other critical performance 

characteristics in the section that follow. 

DOE decided to only consider the minimum frame number series in each product class 

when determining efficiency standards. Therefore, the baseline motors listed in Table 5.2.4 

represent the minimum available frame size in their respective product class. There is more 

detail on the reason for this decision in section 5.6. 

5.2.2 Baseline Models 

For each representative product class selected, DOE identified a specific motor as a 

fundamental design against which it would apply changes to improve the motor’s efficiency. 

These small electric motors were considered DOE’s baseline models. DOE chose these small 

electric motors to represent the characteristics of the least efficient motor for each analyzed 

product class. Because there are no existing minimum energy conservation standards for small 

electric motors, the baseline efficiency was selected after reviewing efficiency ratings suggested 

by manufacturers in the preliminary analyses and product available in the current market. Table 

5.2.4 below shows the efficiencies that DOE found and used as baseline efficiency ratings. Each 

efficiency level listed below is the tested efficiency of a particular motor that DOE purchased, 

tested, and modeled in its subcontractor’s software program. 

Table 5.2.4. Efficiency Ratings of Baseline Motors Selected for Analysis 

Basic Characteristics of Motors Analyzed Baseline Efficiency %

Polyphase, 1 hp, 4-pole, 56 frame 77.2*

CSIR, 1⁄2 hp, 4-pole, 48 frame 57.7

CSCR, 3⁄4 hp, 4-pole, 56 frame 71.0

*The motor purchased was listed at 74%, but was tested at 77.2%. 

As mentioned, DOE tested each motor that was purchased and to be used as a baseline 

model. DOE contracted an independent, accredited laboratory, Advanced Energy, as well as its 

technical expert, Yeadon Energy Systems, to perform the appropriate IEEE test procedure for 

each motor. DOE established dimensional and performance specifications in addition to 

efficiency for the baseline models by examining all outputs of the IEEE test procedures and 

performing teardowns of the purchased motors. The results of the IEEE test procedures provided 

several motor performance characteristics including speed, power factor, torque, and line current 

at various load points. After compiling this test data, DOE’s technical expert tore down each 

motor to obtain dimensions, copper wire gauges, steel grade, and any other pertinent design 

information. Finally, the purchased motors were modeled in the designer’s software and used as 

the baseline designs in each analyzed product class for the engineering analysis. Again, the three 

product classes that were analyzed were: CSIR, 1⁄2 horsepower, 4-pole; CSCR, 3⁄4 horsepower, 4-

pole; and polyphase, 1 horsepower, 4-pole motors. Specific detail on these baseline motors is 

provided in the results section of this chapter, section 5.5. 

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5.3 ENGINEERING ANALYSIS METHODOLOGY 

DOE conducted the engineering analysis using a modified design-option approach where 

DOE employed its technical expert, with motor design software, to develop motor designs at 

several efficiency levels for each analyzed product class. Based on these simulated designs and 

manufacturer and component supplier data, DOE calculated manufacturing costs and selling 

prices associated with each efficiency level. DOE decided on this approach after receiving 

insufficient response to its request for the manufacturer data needed to execute an efficiencylevel, approach for the preliminary analyses. The design-option approach allows DOE to make 

its engineering analysis methodologies, assumptions, and results publicly available, granting 

advocates, manufacturers, and other interested parties the opportunity to review and comment on 

this information. The design options considered in the engineering analysis include: using 

copper die-cast rotor, reducing skew on stack, increasing cross-sectional area of rotor conductor 

bars, increasing end-ring size, changing the gauge of copper wire in stator, manipulating stator 

slot dimensions, decreasing air gap between rotor and stator to 12.5 thousandths of an inch, 

improving grades of electrical steel, using thinner steel laminations, annealing steel laminations, 

adding stack height, using high efficiency lamination materials, changing run-capacitor ratings, 

installing better ball bearings and lubricant, and installing a more efficient cooling system. 

DOE’s technical expert, who specializes in small electric motor designs, prepared six sets 

of designs, two sets for each motor analyzed with each set spanning a range of efficiency levels. 

The third-party software design company determined the fundamental design parameters of the 

baseline motors through the aforementioned testing and teardowns. After modeling the baseline 

motors and creating theoretical, more efficient designs, DOE attempted to validate the results of 

the engineering analysis with the testing and teardown of additional motors available in the 

current market. 

5.3.1 Subcontractor Software Design Approach 

 DOE worked with a subcontractor to develop MSP-efficiency curves for the three 

representative small electric motors. As discussed above, DOE retained a small electric motor 

experta with design experience and software, who prepared multiple sets of designs with 

increasing efficiency. The contractor started by testing the baseline motors purchased according 

to the applicable IEEE test procedure, both IEEE 112 test methods A and B were performed for 

the polyphase motor and IEEE 114 for the two single-phase motors. After testing the motors, the 

subcontractor tore down the motor, measured various dimensions, counted the steel laminations, 

examined the slot fill, and determined all other pertinent design parameters. This data was 

combined and used as inputs to the design software. The resulting designs served duel purposes. 

First, by showing that the output of the software program was in line with the results obtained 

through testing, the subcontractor’s proprietary software program was validated as a design tool. 

DOE feels very confident in its selection of software as it has been used in the past to design, 

prototype, and produce complete induction motor lines. Second, the designs became the starting 

point, or baseline models, against which design options were applied to increase efficiency, for 

each product class analyzed. As new designs were created, careful attention was paid to the 

critical performance characteristics to ensure that the resulting designs were reasonable and 

 

a

 Yeadon Energy Systems, Inc. (YES) of Iron Mountain, Michigan. 

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manufacturable replacements of the baseline motors. To this end, DOE established a set of 

design limitations that are applied across all six sets of designs. 

However, there is one design limitation that is an exception, stack height, and DOE uses 

this design option as a sensitivity analysis. Half of the design sets follow a limitation of no more 

than a 20% increase in stack height, while the other half follow another less stringent restriction 

of no more than a 100% increase in stack height. Both restrictions are listed below and the 

following list presents the all of the design limitations DOE imposed. 

Additionally, one performance characteristic that DOE did not set a limitation on was 

thermal viability. DOE did not do so because the baseline designs for this analysis were created 

by validating actual motors in production today, whereas in the preliminary analysis they were 

theoretical designs. So, for the increasingly efficient, theoretical, designs, DOE assumed that the 

thermal viability would remain because as the efficiency level increases, less heat needs to 

dissipate within the motor and therefore the materials are not subjected to the same strains. 

Peak slot fill – the minimum value of this parameter should exceed 50% while the 

maximum value should not reach more than 65% for an assumed high volume 

simultaneous insertion process. (Note: DOE considers “slot fill” to be the area of the 

wire (including insulation) divided by the total slot area available for winding.) 

Air gap between rotor and stator – the air gap between the rotor and stator should not be 

less than 0.0125 inches for any design. Having air gaps tighter than this minimum could 

be problematic and may cause contact between the spinning rotor and the stationary 

stator, especially as shaft length increases. 

Stator slot opening – the slot opening width in combination with the copper wire gauges 

used should graph to a point in the “Level Wind Area” of the “Blade Gap Chart” taken 

from Alliance Winding1. Without this restriction, DOE is concerned there may be too 

many issues with wire breakage and jamming of manufacturers’ winding tools. 

Locked-rotor torque – for single-phase motors, the locked-rotor torque must be kept 

within 10 percent of the baseline motor, and be within the specifications set forth by 

NEMA MG1-1987 in Section 12.32.2. For polyphase motors there are no NEMA 

specifications, therefore the designs must maintain the locked-rotor torque within 10% of 

the baseline model. 

Locked-rotor current – for single-phase motors, the locked-rotor current should not 

exceed the values of NEMA MG1-1987 Section 12.33.2 (Design N). For polyphase 

motors, the locked-rotor current should not exceed the values shown in NEMA MG1-

1987 Section 12.37 for Design B medium motors. Although there are no requirements 

for small polyphase motors, DOE found that these standards are commonly used in the 

industry. 

Breakdown torque – for single-phase motors, the breakdown torque must fall within 

NEMA MG 1-1987 Table 10-5 limits for all ratings. For polyphase motors, the 

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breakdown torque should follow the guidelines established in NEMA MG1-1987 Section 

12.37. 

Power factor – the power factor of the baseline motor should be maintained or increased 

for all designs. 

Speed at rated load – the speed of the baseline motor should be maintained or increased 

for all designs. 

Service factor – the service factor of each design should be within the limits set forth in 

NEMA MG1-1987 Table 12-2. 

Stray load loss – the assumed value of stray load loss should be 1.8%. 

Motor diameter – the motor diameter of the baseline motor should be that of the baseline 

and remain constant for all designs. 

Cooling system – the parameters directly related to the motor’s cooling system, such as 

ventilation openings in the laminations, should not be modified in a manner that will 

increase the operating temperature of the motor. 

Rotor skew – the rotor skew may be altered, but it cannot be raised or lowered to a point 

that will introduce harmonics that adversely affect motor performance (e.g. completely 

removing it) or introduce cusps in the acceleration curve. (Note: this design limitation is 

subjective and relies on the design of the baseline motor and the expertise of the 

designer). 

Stack height – as mentioned before, DOE’s expert prepared two sets of designs for each 

motor analyzed. The first set of designs for each motor allows a maximum increase in 

stack height of 20% relative to the baseline. The second set of designs are less restricted 

and allow a 100% increase in stack height (i.e. the stack height may double the original 

value). 

Working within these parameters, the subcontractor prepared eight to nine designs of 

increased efficiency for each of the two design sets for each representative motor. The design 

levels prepared for the space constrained designs were at the baseline, intermediate levels, a level 

for a design using a copper rotor, and a max-tech level with a design using a copper rotor and 

exotic core steel. The non-space constrained design (100% increase of stack height) efficiency 

levels corresponded to the efficiency levels created for the space-constrained designs. 

5.3.2 Market Motor Validation 

After DOE created its theoretical designs, DOE attempted to validate those results with 

data from motors currently available in the small electric motors market. DOE selected two to 

three motors from each representative product class, each with a different catalog listed 

efficiency level. DOE then had its subcontractor perform testing on these motors to verify its 

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efficiency level. Next, the motors were torn down and a bill of materials was constructed and 

marked up to create an MSP using the same pricing scheme developed and discussed in section 

5.4. The results of the test data and the MSP developed from the tear downs of these motors 

were plotted along with the curves of the theoretical designs developed for the representative 

units. DOE found that the data points at comparable efficiency levels were consistent with the 

curves of the theoretical designs. The results of this validation analysis are illustrated along with 

the curves developed for the analyzed product classes in appendix 5A. 

5.4 COST MODEL 

 DOE uses a standard method of cost accounting to determine the costs associated with 

manufacturing. This methodology is illustrated in Figure 5.4.1, where production costs and nonproduction costs are combined to determine the manufacturer selling price (MSP). 

Figure 5.4.1. Standard Method of Cost Accounting for Standards Rulemaking 

 DOE developed estimates of some of the cost multipliers shown in Figure 5.4.1 by 

reviewing Security and Exchange Commission (SEC) SEC-10K reports from A.O. Smith 

Corporation, Baldor Electric Company, Emerson Motor Technologies, Regal-Beloit Corporation, 

and WEG Electric Corporation as well as through conversations with industry experts. Together, 

the full production cost or manufacturer production cost (MPC) and the non-production costs 

equal the MSP. Full production cost is a combination of direct labor, direct materials, and 

Direct

Labor

Direct

Labor

Direct

Material

Direct

Material Overhead Overhead Selling Selling General &

Admin. Admin. R & D R & D Interest Interest

Indirect Labor

Full Production Cost*

(Manufacturer Production Cost)

Non-Production Cost

Indirect Material

Maintenance

Depreciation

Taxes

Insurance related

to assets

Mkt. research

Advertising

POSpromotion

Sales person

salary + travel

+ commission

Logistics

- Warehousing

- Delivery

- Record

 keeping

- Order entry/

 processing

Costs of

service &

staff units

General

corporate

costs

- comp. etc.

Costs

associated

with efforts

to find new

or improved

products or

production

processes

Costs

of

borrowing

funds

*

 

Tax Reform Act of 1986, essentially, requires companies to measure cost of goods sold as the full production cost of the goods sold.

Full Cost of Product Manufacturer Selling Price

Code

compliance

Modernization

Cust. service

EERE-2007-BT-STD-0007 COMMENT 33
5-14 

overhead. The overhead contributing to full production cost includes indirect labor, indirect 

material, maintenance, depreciation, taxes, and insurance related to company assets. Nonproduction costs include the cost of selling (market research, advertising, sales representatives, 

logistics), general and administrative costs, research and development, interest payments and 

profit factor (not shown in the figure).

After the subcontractor designs were completed and verified for manufacturability (i.e., 

following the design limitations mentioned in section 5.3.1), the next step was applying this cost 

model to all of them. A standard bill of materials (BOM) was constructed that includes direct 

material costs and labor time estimates along with costs. The BOM is then multiplied by a 

markup for overhead to obtain an MPC which in turn is marked up again for non-production 

costs to create a MSP. 

5.4.1 Constructing a Bill of Materials 

The BOM calculated for each design contained three types of material costs: fixed costs, 

variable costs, and semi-fixed costs. Fixed cost materials are those components that remain 

constant across all designs within a set. That is, these are the parts that do not vary with 

efficiency, such as switches, ball-bearings and other components. The aggregate fixed cost will 

vary from one motor category to another because the different motor categories have different 

component lists, but for a given motor category the total fixed costs remain constant for all 

designs. The variable costs considered are those portions of the BOM that vary based on the cost 

of the material and the amount of that material used in the design. For example, stator and rotor 

lamination costs are variable costs because the material price for the different steel grades 

changes as does the volume of steel needed for each design. Finally, semi-fixed costs are those 

materials that have a constant price, but vary in cost from design to design as a function of the 

amount used in the motor designs. An example of this is the cost of the die-cast aluminum or 

copper rotor bars. The price per pound for aluminum or copper is the same from design to 

design; however, the cost per design is different because the amount of metal used for die-casting 

the rotor bars varies depending upon the design (e.g. a longer motor will require more 

aluminum). 

DOE presents a detailed bill of materials for one design from each of the three motor 

categories analyzed in TSD appendix 5A. The discussion below describes the level of detail 

contained in the bill of materials presented in this appendix. 

Each item in the BOM is organized by the component of the motor to which they apply. 

For example “end cap assembly” is a heading and under this label there are several itemized 

parts with associated costs. The BOM includes the following headings, each with an itemized 

parts list: stator assembly, rotor assembly, end cap assembly, housing assembly, hardware, and 

final assembly. 

As mentioned, each heading has an itemized list of components. The stator assembly’s 

itemized lists include prices for cleats, lead wires, capacitor wires (for appropriate motor 

categories), splices, insulation, slot liner, copper shipping, stator laminations, main and auxiliary 

(when applicable) copper wire costs. The rotor assembly portion of the BOM includes prices for 

a fan, bearings, the rotor aluminum or copper, and the lamination costs. The housing assembly 

EERE-2007-BT-STD-0007 COMMENT 33
5-15 

list includes paint, a fan shroud, a base, and the actual housing costs. Much of the hardware costs 

are fixed and include prices for washers, capacitor covers (when applicable), mounting bolts, cap 

screws, thermal switch screws, terminal block screws, terminal cover screws, studs, conduit cap, 

a start switch (when applicable), a nameplate, as well as some variable costs for start and run 

capacitors (when applicable). 

5.4.2 Commodity Prices 

 A significant portion of the costs associated with small electric motors is attributed to the 

fluctuating metal prices of several motor components. These include steel laminations, copper 

wiring, and rotor die-casting aluminum or copper. DOE understands that it is difficult to choose 

an accurate price point for these components because their underlying commodity prices have 

seen great fluctuations over the past several years, translating into large variations in cost. As a 

best estimate for these prices, DOE used an inflation adjusted five-year average price point for 

these components. In calculating the five-year average prices for these commodities, DOE 

adjusted historical prices to $2008 using the historical Bureau of Labor Statistics Producer Price 

Indices (PPI) for each commodity’s industry2

. 

Additionally, DOE performed a cost sensitivity analysis in which they examined both a 

high and low commodities cost scenario. For all commodity prices, DOE used the PPI to 

determine the high and low cost points and then input those component costs into the model. 

This allowed DOE to generate a high commodities case and a low commodities case for the 

engineering analysis results. Please see appendix 5A for greater detail on the high and low cost 

scenarios. 

DOE utilized the PPI for each commodity’s industry to calculate these prices. The PPI is 

an index that tracks the average change in prices that domestic producers receive for their 

product. This allowed DOE to scale its current 2008 component prices back for the previous five 

years for an inflation adjusted comparison. Once DOE had prices for 2004 through 2008, it was 

able to take a five-year average of these prices, as well as determine the maximum and minimum 

prices over the time period. The following figures depict the component prices over the fiveyear timeframe. 

EERE-2007-BT-STD-0007 COMMENT 33
5-16 

$2.20

$2.30

$2.40

$2.50

$2.60

$2.70

$2.80

$2.90

$3.00

$3.10

$3.20

2003 2004 2005 2006 2007 2008 2009 $/lb

Year

Copper Wire Prices (in 2008 US$)

18 Gauge

19 Gauge

20 Gauge

21 Gauge

22 Gauge

Figure 5.4.2. Five-Year Copper Wire Prices in $2008 US 

$0.00

$0.50

$1.00

$1.50

$2.00

$2.50

2003 2004 2005 2006 2007 2008 2009 $/lb

Year

Copper

Aluminum

Figure 5.4.3. Five-Year Die-Casting Prices in $2008 US 

EERE-2007-BT-STD-0007 COMMENT 33
5-17 

$0.00

$0.05

$0.10

$0.15

$0.20

$0.25

$0.30

$0.35

$0.40

$0.45

2003 2004 2005 2006 2007 2008 2009 $/lam

Year

Core Steel Stator Prices (in 2008 US$)

29M15

24M19

24M56

Figure 5.4.4. Five-Year Steel Lamination Prices in $2008 US 

5.4.3 Labor Costs and Assumptions 

Due to the degree of automation used in manufacturing small electric motors, labor costs 

are not a significant portion of the overall production cost and do not vary significantly with 

increasingly efficient designs. The modeling software provides an estimate of the amount of 

labor associated with each small electric motor design. DOE then multiplies that time estimate 

by a marked up hourly rate to determine the proportion of labor cost associated with the 

manufacturer’s production cost.

DOE used the same hourly labor rate for all motors analyzed. The base hourly rate was 

developed from the 2002 Economic Census of Industry3 by the U.S. Census Bureau. Several 

markups were applied successively and with cumulative effect to the base hourly rate to obtain a 

fully burdened rate which was intended to be representative of the labor costs associated with 

manufacturing these motors. Table 5.4.1 shows the base labor rate DOE started with, each 

markup with its corresponding markup percentage and the resulting partially burdened rate after 

that markup, and a final fully burdened labor rate. The markups were applied in the order they 

appear in the table and to the “rate per hour” listed for the previous markup. For example, the 28 

percent markup for fringe was applied to the $18.02 (i.e., 1.28 x $18.02 = $23.07) that DOE 

obtained after marking up the base labor rate by 33 percent for indirect production. 

EERE-2007-BT-STD-0007 COMMENT 33
5-18 

Table 5.4.1. Labor Markups for Small Electric Motor Manufacturers

Item description Markup Rate per hour

Labor cost per hour $ 13.55

Indirect Production 33 % $ 18.02

Fringe† 28 % $ 23.07

Assembly Labor Up-time†† 43 % $ 32.99

Cost of Labor Input to Spreadsheet $ 32.99

 Cost per hour is from U.S. Census Bureau, 2002 Economic Census of Industry, published December 2004, Table 

5, page 5. Data for NAICS code 3353121 “Fractional Horsepower Motors” Production workers hours and wages.

 Indirect Production Labor (Production managers, quality control, etc.) as a percent of direct labor on a cost basis. 

Navigant Consulting, Inc. NCI estimate.

† Fringe includes pension contributions, group insurance premiums, workers compensation. Source: U.S. Census 

Bureau, 2002 Economic Census of Industry, published December 2004, Table 3, page 3. Data for NAICS code 

335312 “Motors and generator manufacturing,” total fringe benefits as a percent of total compensation for all 

employees (not just production workers). 

†† Assembly labor up-time is a factor applied to account for the time that workers are not assembling product 

and/or reworking unsatisfactory units. The markup of 43 percent represents a 70 percent utilization (multiplying by 

100/70). NCI estimate. 

 As discussed above, the small electric motor design software provides an estimated 

manufacturing time for each design. The software apportions the labor time estimates into 

categories that identify an overall activity, such as stator assembly, rotor assembly, and housing 

assembly. Within these categories, subheadings denote process steps for specific parts of the 

motor. Summing the list of process steps gives a total time estimate for manufacturing the motor, 

which is multiplied by the fully burdened labor cost, shown as $32.99. 

 In consultation with manufacturers, DOE learned that the amount of time necessary to 

build a motor with a longer stack or more copper wirings is considered negligible. Therefore, 

there was only one process step that DOE calculated as a variable labor cost, namely the “Rotor 

Core Assembly” process. This activity changed to a longer time when the subcontractor’s 

designs called for a copper rotor. The reason for the increased labor time is because copper has a 

higher melting point than aluminum does, so die-casting the rotor takes more time to heat the 

metal sufficiently. 

 The remainder and the majority of the labor costs calculated were fixed costs. The 

following categories are associated with the labor estimates: stator assembly, rotor assembly, 

end cap assembly, housing assembly, hardware, and final assembly. The stator assembly list 

includes time estimates for punching and stacking the laminations, adding slot liner, winding 

coils, inserting coils, forming end-turns, lead stripping and terminal placement, magnet wire or 

lead splicing, using the stator test system, and applying the varnish. Adding the fan, machining 

the shaft, pressing the shaft onto the rotor, balancing the rotor, and heat shrinking bearings onto 

the shaft are labor steps for the rotor assembly. For end cap assembly there are time estimates for 

machining the bearing bore at each end, pressing the cap, washing, and performing the die-cast 

press. The labor times under the hardware section are estimates of adding the components to the 

motor. Various washers, bolts, studs, screws, grommets for capacitor wire (when applicable), 

start and/or run capacitors (when applicable), and a start switch (when applicable) are among 

EERE-2007-BT-STD-0007 COMMENT 33
5-19 

these hardware components. Included in the final assembly section are times for actual assembly, 

motor testing, labeling and packaging. 

5.4.4 Manufacturer Markups 

 DOE used the three markups described below to account for costs that are part of each 

motor leaving a manufacturer’s facility. Scrap factors, overhead costs, and non-production 

markups will vary from manufacturer to manufacturer because their profit margins, prices paid 

for goods, and business structures vary. DOE prepared estimates for these three non-production 

cost manufacturer markups from SEC-10K reports and conversations with manufacturers and 

experts. 

Handling and scrap factor: 2.5 percent markup. This markup was applied to the direct 

material production costs of each motor. It accounts for the handling of material (loading 

into assembly or winding equipment) and the scrap material that cannot be used in the 

production of a finished small electric motor (e.g., lengths of wire too short to wind). 

Factory overhead: 17.5 or 18.0 percent markup. Factory overhead includes all the 

indirect costs associated with production, indirect materials and energy use, taxes, 

insurance, and depreciation. DOE applies factory overhead to the direct material 

production costs, including the handling and scrap factor, and labor estimates. For 

aluminum rotor designs a 17.5 percent markup was used, but for all copper rotor designs 

an 18.0 percent markup was used to factor in increased depreciation for the equipment. 

Non-production: 45 percent markup. This markup reflects costs including sales and 

general administrative, research and development, interest payments, and profit factor. 

DOE applies the non-production markup to the sum of the direct material production, the 

handling and scrap, the direct labor, and the factory overhead otherwise known as the 

MPC. The MPC plus the non-production markup gives a manufacturer selling price 

MSP. 

5.5 RESULTS OF ENGINEERING ANALYSIS 

 For the polyphase and CSIR motors analyzed, DOE developed eight efficiency levels 

using a motor design software tool, and for the CSCR motor analyzed DOE developed nine 

efficiency levels. These included a baseline design, intermediate designs, then a copper rotor 

design, and a max-tech design that uses a copper rotor and an exotic core steel. Then by using 

the methodology and pricing scheme outlined in the previous section, DOE developed 

manufacturer selling prices for each small electric motor design created. Throughout this 

section, DOE shows the bottoms-up derived MSP’s. 

 The engineering analysis results are essentially six manufacturer selling price-versus-fullload efficiency curves that represent two relationships for each of the three representative 

product classes analyzed. For each of the three motors analyzed, DOE created designs that 

allowed stack height to double and designs that only allowed stack height to increase by 20 

percent over the baseline design. This was done to determine how the cost-efficiency 

EERE-2007-BT-STD-0007 COMMENT 33
5-20 

relationship would change for space constrained OEMs (only 20 percent increase) versus nonspace constrained OEMs (doubled stack height maximum). Thus, each of the three motors 

analyzed have two curves plotted to depict these two scenarios. The six graphs shown in Figure 

5.5.1 through Figure 5.5.6 provide the MSP versus efficiency curves and Table 5.5.1 through 

Table 5.5.6 present the tabulated results. 

5.5.1 Polyphase, 1 Horsepower, 4-Pole, 56-Frame Motor 

Figure 5.5.1 presents the relationship between the MSP and full-load efficiency for the 

polyphase motor analyzed. DOE developed an exotic maximum technology (max-tech) design 

using a non-traditional steel type (i.e., Hiperco 50TM) that makes the motor considerably more 

expensive than other designs analyzed. Use of this premium electromagnetic steel greatly 

increases the MSP of the motor, thereby skewing the Y-axis. For this reason, the engineering 

analysis results are presented twice, first with the max-tech design (Figure 5.5.1) and then again 

without the max-tech design (Figure 5.5.2). 

$0

$200

$400

$600

$800

$1,000

$1,200

$1,400

$1,600

$1,800

$2,000

Manufacturer Selling Price ($2008)

76 78 80 82 84 86 88 90

Full Load Efficiency (%)

Space Constrained

Non-Space 

Constrained

Figure 5.5.1. Polyphase 1 Horsepower, 4-Pole, 56-Frame Motor Engineering 

Analysis, with Maximum Technology Point 

EERE-2007-BT-STD-0007 COMMENT 33
5-21 

$0

$50

$100

$150

$200

$250

$300

$350

Manufacturer Selling Price ($2008)

76 78 80 82 84 86 88 90

Full Load Efficiency (%)

Space Constrained

Non-Space 

Constrained

Figure 5.5.2. Polyphase 1 Horsepower, 4-Pole, 56-Frame Motor Engineering Analysis, 

without Maximum Technology Point 

 Table 5.5.1 presents the same engineering analysis results in a tabular form, including the 

full-load efficiency values and the MSPs. Moving from the baseline motor to the max-tech 

motor, DOE found that the full-load efficiency would increase 11.1 percentage points, for a 14.5-

percent improvement over the baseline motor. Raising the efficiency to that level caused the 

MSP to more than triple, increasing from $97.74 for the baseline model to $324.66 for the nonspace constrained max-tech motor. The difference in MSP is even greater for the spaceconstrained max-tech motor, which has a MSP of $1,770.27. 

Table 5.5.1. Efficiency and MSP Data for Polyphase Motor 

Efficiency Level Efficiency %

(Design 1 / Design 2)*

MSP $

(Design 1 / Design 2)*

Baseline 77.2 % $ 97.74

EL 1 78.7 % $ 103.81

EL 2 80.0 % $ 107.01

EL 3 81.6 % $ 112.88

EL 4 82.5 % $ 117.01

EL 5 85.2 % / 85.2 % $ 229.84 / $ 150.86

EL 6 86.7 % / 86.4 % $ 236.20 / $ 184.73

EL 7 (Max-tech) 88.3 % / 88.4 % $ 1,770.27 / $ 324.66

*Design 1 denotes the space constrained design, and design 2 denotes the non-space constrained design. If only one 

value is listed, then the space constrained design is the same as the non-space constrained design. 

EERE-2007-BT-STD-0007 COMMENT 33
5-22 

Table 5.5.2 presents some of the design and performance specifications associated with 

the eight polyphase designs presented above. Additionally, DOE provides more details and 

performance characteristics for polyphase designs in appendix 5A. 

Table 5.5.2. Polyphase, 1 Horsepower, 4-Pole, 56-Frame Motor Designs 

Parameter 

(Units) Baseline EL1 EL2 EL3 EL4 EL5 EL6 EL7

- -

Design 1

Design 2

Design 1

Design 2

Design 1 

Design 2

Design 1

Design 2

Design 1

Design 2

Design 1 

Design 2

Design 1 

Design 2

Efficiency 

(%) 77.2 78.7 80.0 81.6 82.5 85.285.2

86.7

86.4

88.3

88.4

Power 

Factor 71.6 71.3 71.9 74.2 73.8 71.874.7

72.4

74.5

71.9

72.0

Speed 

(RPM) 1714 1728 1726 1720 1724 17191722

1736

1728

1736

1753

Torque 

(in-lbs)

36.8 36.7 36.8 36.7 36.6 36.7

36.8

36.6

36.6

36.6

35.6

Current 

(A) 3.38 3.35 3.29 3.10 3.08 3.062.96

3.00

2.92

2.97

2.91

Core Steel 24M56 24M56 24M56 24M56 24M56 29M15

24M19

29M15

24M19

Hiperco 50

29M15

Stack Height

(in) 3.0 3.2 3.425 3.5 3.6 3.64.45

3.6

6

3.6

5.525

Rotor

Material Al Al Al Al Al AlAl

Cu

Al

Cu

Cu

Main Wire 

(AWG) 22 21 20.5 20 19.5 19.521

19.5

20

19.5

20

LR Torque 

(in-lbs)

76.1 79.1 80.3 73.4 73.0 81.0

77.1

63.7

80.6

63.7

72.7

LR Current

(A) 16.6 17.5 17.3 15.8 16.1 16.416.2

16.3

17.0

16.3

19.5

Service 

Factor 1.15 1.15 1.15 1.15 1.15 1.151.15

1.15

1.15

1.15

1.15

*Design 1 denotes the space constrained design, and design 2 denotes the non-space constrained design. If only one 

value is listed, then the space constrained design is the same as the non-space constrained design. 

5.5.2 Capacitor-Start, Induction-Run, 1/2 Horsepower, 4-Pole, 48-Frame Motor 

 Figure 5.5.3 presents the relationship between the MSP and full-load efficiency for the 

48-frame capacitor-start, induction-run motor DOE analyzed. The max-tech design incorporates 

a high-grade non-traditional electromagnetic steel (Hiperco 50TM) alloy that is much more 

expensive than the high quality electromagnetic steel alloy used in any of the other designs. Use 

of such steel greatly increases the MSP of the motor, thereby skewing the Y-axis. For this 

reason, the engineering analysis results are presented again without the max-tech design in 

Figure 5.5.4. 

EERE-2007-BT-STD-0007 COMMENT 33
5-23 

$0

$200

$400

$600

$800

$1,000

$1,200

$1,400

Manufacturer Selling Price ($2008)

55 60 65 70 75 80

Full Load Efficiency (%)

Space Constrained

Non-Space 

Constrained

Figure 5.5.3. Capacitor-Start, Induction-Run, 1⁄2 Horsepower, 4-Pole, 48-Frame 

Engineering Analysis Curve, with Maximum Technology Point 

$75

$95

$115

$135

$155

$175

$195

Manufacturer Selling Price ($2008)

55 60 65 70 75 80

Full Load Efficiency (%)

Space Constrained

Non-Space 

Constrained

Figure 5.5.4. Capacitor-Start, Induction-Run, 1⁄2 Horsepower, 4-Pole, 48-Frame 

Engineering Analysis Curve, without Maximum Technology Point 

 Table 5.5.3 presents the same engineering analysis results in a tabular form, including the 

full-load efficiency values and the MSPs. Moving from the baseline motor to the max-tech 

EERE-2007-BT-STD-0007 COMMENT 33
5-24 

motor, DOE found that the full-load efficiency would increase 19.3 percentage points, for about 

a 33-percent improvement over the baseline motor. Raising the efficiency to that level caused the 

MSP to increase by more than 65 percent, increasing from $91.04 for the baseline model to 

$150.70 for the non-space constrained max-tech motor. The difference in MSP is significantly 

greater for the space-constrained max-tech motor, which has a MSP of $1,204.30. 

Table 5.5.3. Efficiency and MSP Data for Capacitor-Start, Induction-Run, 48-Frame 

Motor 

Efficiency Level Efficiency %

(Design 1 / Design 2)*

MSP $

(Design 1 / Design 2)*

Baseline 57.7 % $ 91.04

EL 1 59.5 % $ 95.62

EL 2 62.0 % $ 98.54

EL 3 64.2 % $ 99.78

EL 4 68.5 % / 68.6 % $ 114.57 / $ 107.19

EL 5 71.2 % / 71.2 % $ 118.98 / $ 120.53

EL 6 73.0 % / 73.1 % $ 182.28 / $ 132.16

EL 7 (Max-tech) 77.0 % / 77.2 % $ 1,204.30 / $ 150.70

*Design 1 denotes the space constrained design, and design 2 denotes the non-space constrained design. If only one 

value is listed, then the space constrained design is the same as the non-space constrained design. 

 Table 5.5.4 presents some of the design and performance specifications associated with 

the eight CSIR efficiency levels presented above. Additionally, DOE provides more details and 

performance characteristics for CSIR designs in appendix 5A. 

EERE-2007-BT-STD-0007 COMMENT 33
5-25 

Table 5.5.4. Capacitor-Start, Induction-Run, 1/2 Horsepower, 4-Pole, 48-Frame Motor 

Designs 

Parameter 

(Units) Baseline EL1 EL2 EL3 EL4 EL5 EL6 EL7

- -

Design 1

Design 2

Design 1

Design 2

Design 1 

Design 2

Design 1

Design 2

Design 1

Design 2

Design 1 

Design 2

Design 1 

Design 2

Efficiency 

(%) 57.7 59.5 62.0 64.2 68.568.6

71.2

71.2

73.0

73.1

77.0

77.2

Power 

Factor 59.4 59.2 59.4 62.1 61.567.3

59.6

68.6

62.0

62.0

67.2

65.3

Speed 

(RPM) 1723 1722 1722 1722 17231732

1749

1735

1739

1744

1736

1760

Torque 

(in-lbs)

18.4 18.3 18.5 18.5 18.3

18.5

18.0

18.2

18.2

18.1

18.3

17.9

Current 

(A) 9.12 8.84 8.48 7.85 7.536.77

7.42

6.32

7.07

6.91

6.26

6.27

Core Steel .028M56 24M56 24M56 24M56 24M19

24M56

24M19

24M56

29M15

24M19

Hiperco 50

24M19

Stack Height

(in) 2 2.1 2.2 2.3 2.42.9

2.4

4

2.4

3.275

2.4

4

Rotor

Material Al Al Al Al AlAl

Cu

Al

Cu

Al

Cu

Cu

Main Wire 

(AWG) 18.5 21 20.5 20.5 20.520

20.5

21

20.5

21

20.5

21

Aux. Wire

(AWG) 21.5 21.5 21.5 21.5 21.521.5

21.5

21.5

21.5

21.5

21.5

21.5

Start Cap.

(μF) 333 333 333 333 333 333 333 333

LR Torque 

(in-lbs)

51.0 50.2 50.6 50.2 50.6

52.6

50.7

51.6

50.1

50.7

51.6

47.6

LR Current

(A) 38.0 37.4 37.4 35.9 35.335.3

36.0

34.9

34.3

39.2

32.1

35.9

Service 

Factor 1.25 1.25 1.25 1.25 1.251.25

1.25

1.25

1.25

1.25

1.25

1.25

*Design 1 denotes the space constrained design, and design 2 denotes the non-space constrained design. If only one 

value is listed, then the space constrained design is the same as the non-space constrained design. 

5.5.3 Capacitor-Start, Capacitor-Run, 3/4 Horsepower, 4-Pole, 56-Frame Motor 

Figure 5.5.5 presents the relationship between the MSP and full-load efficiency for the 

CSCR motor. The max-tech design incorporates a high-grade non-traditional electromagnetic 

steel alloy (Hiperco 50TM) that is much more expensive than the high quality electromagnetic 

steel alloy used in any of the other designs. Use of such steel greatly increases the MSP of the 

motor, thereby distorting the Y-axis. For this reason, the engineering analysis results are 

presented again without the max-tech design in Figure 5.5.6. 

EERE-2007-BT-STD-0007 COMMENT 33
5-26 

$0

$200

$400

$600

$800

$1,000

$1,200

$1,400

$1,600

$1,800

$2,000

Manufacturer Selling Price ($2008)

70 75 80 85 90

Full Load Efficiency (%)

Space Constrained

Non-Space 

Constrained

Figure 5.5.5. Capacitor-Start, Capacitor-Run 3⁄4 Horsepower, 4-Pole, 56-Frame 

Engineering Analysis Curve, with Maximum Technology Point 

$75

$125

$175

$225

$275

$325

$375

70 75 80 85 90

Manufacturer Selling Price ($2008)

Full Load Efficiency (%)

Space Constrained

Non-Space 

Constrained

Figure 5.5.6. Capacitor-Start, Capacitor-Run 3⁄4 Horsepower, 4-Pole, 56-Frame 

Engineering Analysis Curve, without Maximum Technology Point 

EERE-2007-BT-STD-0007 COMMENT 33
5-27 

 Table 5.5.5 presents the same engineering analysis results in tabular form, including the 

full-load efficiency values and the MSPs. Moving from the baseline motor to the max-tech 

motor, DOE found that the full-load efficiency would increase 16.3 percentage points, for about 

a 23-percent improvement over the baseline motor. Raising the efficiency to that level caused the 

MSP to more than triple, increasing from $110.82 for the baseline model to $353.50 for the nonspace constrained max-tech motor. The difference in MSP is significantly greater for the spaceconstrained max-tech motor, which has a MSP of $1,778.48. 

Table 5.5.5. Efficiency and MSP Data for Capacitor-Start, Capacitor-Run Motor 

Efficiency Level Efficiency %

(Design 1 / Design 2)*

MSP $

(Design 1 / Design 2)*

Baseline 71.0 % $ 110.82

EL 1 74.3 % $ 116.06

EL 2 78.3 % / 78.4 % $ 136.22 / $ 128.60

EL 3 80.3 % / 80.5 % $ 141.49 / $ 133.71

EL 4 81.6 % / 81.8 % $ 145.27 / $ 141.10

EL 5 82.7 % / 82.9 % $ 152.88 / $ 149.23

EL 6 83.7 % / 83.5 % $ 237.53 / $ 156.85

EL 7 85.4 % / 85.6 % $ 245.36 / $ 172.75

EL 8 (Max-tech) 87.3 % / 87.3 % $ 1,778.48 / $ 353.50

*Design 1 denotes the space constrained design, and design 2 denotes the non-space constrained design. If only one 

value is listed, then the space constrained design is the same as the non-space constrained design. 

 Table 5.5.6 presents some of the design and performance specifications associated with 

the nine CSCR efficiency levels presented above. Additionally, DOE provides more design 

details and performance characteristics for CSCR designs in appendix 5A. 

EERE-2007-BT-STD-0007 COMMENT 33
5-28 

Table 5.5.6. Capacitor-Start, Capacitor-Run, 3/4 Horsepower, 4-Pole, 56-Frame Motor 

Parameter 

(Units) Baseline EL1 EL2 EL3 EL4 EL5 EL6 EL7 EL8

-

Design 1

Design 2

Design 1

Design 2

Design 1 

Design 2

Design 1

Design 2

Design 1

Design 2

Design 1 

Design 2

Design 1 

Design 2

Design 1 

Design 2

Efficiency

(%) 71.0 74.3 78.378.4

80.3

80.5

81.6

81.8

82.7

82.9

83.7

83.5

85.4

85.6

87.3

87.3

Power

Factor 68.6 77.1 75.183.9

80.1

83.4

90.7

96

92.2

95.9

94.6

99.2

93.1

97.5

90.6

99.4

Speed

(RPM) 1735 1740 17421731

1742

1735

1744

1753

1769

1763

1733

1760

1762

1765

1764

1755

Torque

(oz-ft) 27.4 27.3 27.227.3

27.4

27.4

27.2

27.1

27.0

27.0

27.3

27.1

26.9

26.6

26.9

27.1

Current

(A) 10.1 8.53 8.307.40

7.66

7.29

6.58

6.23

6.40

6.16

6.16

5.92

6.18

5.78

6.17

5.64

Core

Steel 24M56 24M56 24M1924M56

24M19

24M56

24M19

24M56

24M19

24M56

29M15

24M56

29M15

24M19

Hiperco 50

29M19

Stack Height

(in) 3 3.15 3.34.1

3.45

4.6

3.6

4.5

3.6

5

3.6

5.5

3.6

4.75

3.6

6

Rotor Material Al Al Al

Al

Al

Al

Al

Cu

Cu

Cu

Al

Cu

Cu

Cu

Cu

Cu

Main Wire

(AWG) 18 20.5 20.520.5

20

21.5

20

21.5

20

21.5

20

21.5

20

21.5

20

21.5

Aux. Wire

(AWG) 19 21.5 21.521.5

21

21

21

21

21

21

19

21

19

21

21.5

21

Start Cap.

(μF) 433 433 433433

433

433

433

433

433

433

433

433

433

433

433

433

Run Cap.

(μF) 7.5 20 2020

25

25

35

35

40

40

40

45

45

45

35

45

LR Torque

(oz-ft) 76.4 77.7 78.085.5

81.1

78.3

77.6

75.6

79.0

76.8

71.6

73.8

71.7

76.4

77.2

71.6

LR Current

(A) 53.2 53.1

54.3

47.3

54.3

34.6

52.1

47.1

58.4

44.7

45.2

45.0

47.4

43.9

47.8

42.9

Service Factor 1.25 1.25 1.25

1.25

1.25

1.25

1.25

1.25

1.25

1.25

1.25

1.25

1.25

1.25

1.25

1.25

*Design 1 denotes the space constrained design, and design 2 denotes the non-space constrained design. If only one value is listed, then the space constrained 

design is the same as the non-space constrained design. 

EERE-2007-BT-STD-0007 COMMENT 33
5-29 

5.6 SCALING RELATIONSHIPS 

 In order to reduce the analytical burden associated with conducting a detailed engineering 

analysis of the cost-efficiency relationship on all 72 product classes, DOE developed a 

systematic approach that reduced the number of small electric motors it analyzed while retaining 

reasonable levels of accuracy. DOE selected one baseline model from each motor category to 

evaluate in the engineering analysis. It then extrapolated the results of this analysis from the 

units studied to the other product classes. This section describes the methodology DOE followed 

to scale to product classes that were not directly analyzed. 

 To scale to the product classes that were not analyzed, DOE followed a few steps. First, 

DOE compiled efficiency data for as many manufacturers and product classes as possible. Then 

the data was filtered to ensure an accurate representation of the small electric motors that are 

covered by the statute. Next, DOE modeled the efficiency data in terms of motor losses to fill in 

any potential gaps in data. An independently accredited laboratory validated the efficiency data 

by testing certain small electric motors according to the applicable IEEE test procedures: IEEE 

112 (test methods A and B) for polyphase motors and IEEE 114 for single-phase motors. 

Finally, DOE scaled the results of the engineering analysis based on the relationships found from 

the combined catalog and test data. 

5.6.1 Market Efficiency Data 

 To determine the existing efficiency relationships between product classes, DOE 

examined all the publicly available efficiency data for small electric motors covered by this 

rulemaking. DOE compiled available catalog data and online listings for polyphase, CSIR, and 

CSCR motors to see how efficiency changes across different pole configurations and with 

varying horsepower ratings. DOE developed a database of over 3,000 motors built in a NEMA 

two-digit frame sizes. This database was filtered to create a comprehensive list of motors that 

met the statutory definition of a small electric motor. DOE also filtered the database to only 

include efficiency data for the smallest frame series seen for each product class. The smallest 

frame series for a given product class is the most restricted frame series in terms of possible 

efficiency. The reason for this is that there is less room there is to add core material (in terms of 

diameter), which helps increase efficiency, therefore any efficiency the smallest frame series 

motor can achieve should also be achievable for the larger frame series in the same product class. 

Additionally, individual manufacturer motor lines were examined independently so that design 

characteristics (e.g. steel grade) would be consistent. Since each manufacturer was looked at 

individually, if a manufacturer did not have a nearly complete product line, or if the 

manufacturer did not provide enough efficiency data to create an accurate assessment of the 

product line, then that manufacturer’s data was not included in the initial efficiency relationship 

data set. 

5.6.2 Independently Tested Motor Results 

At the time of this data collection and analysis, there were no energy-efficiency standards 

or mandated test procedures for small electric motors. Therefore, when one manufacturer lists 

EERE-2007-BT-STD-0007 COMMENT 33
5-30 

efficiency in their catalog it was not necessarily calculated and reported in the same way that 

another manufacturer calculates and reports it. So, DOE contracted an independently accredited 

electric motor testing company. In addition to using catalog data and online listings to determine 

the existing efficiency relationship between product classes, DOE purchased and tested a sample 

product line of polyphase and CSIR motors to verify efficiency relationships. DOE was unable 

to purchase and test a complete product line of CSCR motors because no manufacturers currently 

offer a complete product line of this motor category. This issue is discussed further in Section 

5.6.5 dealing with CSCR scaling. This data was intended to validate the efficiency relationships 

seen across product classes, not necessarily to confirm the value of efficiency listed by the 

manufacturer. Results of this testing are available in appendix 5A. 

5.6.3 Modeling Small Electric Motor Efficiency 

After compiling the catalog and test data, DOE modeled the data and began drawing 

conclusions about the relationship between product class and efficiency. To do this DOE 

converted efficiency into motor losses using the equation: (100/μ) – 1, where μ is full-load 

efficiency. By converting the efficiency data into motor losses, DOE could generate the most 

accurate line of best fit. DOE used a power equation to model motor losses and then plotted the 

results, for each manufacturer, on graphs with logarithmic axes. Using the generated equations, 

DOE interpolated and extrapolated the catalog and test data to approximate data for any gaps of 

information. This allowed DOE to generate complete sets of data, a set being the 24 product 

classes within a motor category. After modeling motor losses for the various manufacturers’ 

data, DOE aggregated the data to obtain an average picture of motor losses (and therefore 

efficiency) for the current market. The aggregated results are shown in Figure 5.6.1 and Figure 

5.6.2. The plots show that the data can be graphed linearly, which eases interpretation of trends 

in motor losses. 

y = 32.479x-0.402

R2 = 0.9463

y = 31.591x-0.482

R2 = 0.9777

y = 31.352x-0.328

R2 = 0.9845

1 0

100

0.1 1 1 0

Motor Losses

Horsepower Rating

Market Average Motor Losses for Polyphase Motors

Two-Pole

Four-Pole

Six-Pole

EERE-2007-BT-STD-0007 COMMENT 33
5-31 

Figure 5.6.1. Manufacturer Motor Losses for Polyphase Motors 

y = 47.57x-0.395

R2 = 0.9857

y = 41.784x-0.474

R2 = 0.9952

y = 37.342x-0.725

R2 = 0.9918

1 0

100

0.1 1 1 0

Motor Losses

Horsepower Rating

Market Average Motor Losses for CSIR Motors

Two-Pole

Four-Pole

Six-Pole

Figure 5.6.2. Manufacturer Motor Losses for CSIR Motors 

Each figure is unique for a certain motor category and each figure contains three lines, 

one for each pole configuration. Also, the graphs shown are of the aggregated market data, but 

DOE did create these graphs for each manufacturer for which efficiency data was compiled. 

Prior to aggregating the individual manufacturer data, DOE used the equations of the lines of 

best fit to interpolate and extrapolate any missing motor loss data for a given product class. For 

example, if manufacturer A did not produce a polyphase, two pole 1⁄4 horsepower motor, DOE 

could use an equation, unique to manufacturer A and polyphase, two-pole motors to estimate 

what the motor losses would be. This process was used to fill in any gaps in a manufacturer’s 

product line so that a manufacturer’s motor loss table would be completely filled out. This 

process was implemented for all manufacturers where there was enough data to interpret a 

complete product line. Generating data to create complete product lines for the various 

manufacturers was necessary to prevent uneven waiting of manufacturer trends. DOE 

understands that each manufacturer targets different performance characteristics that can 

ultimately affect the efficiency of the motor. Therefore, DOE estimated what motor losses, and 

thus efficiency, would be for motors that are not necessarily produced by some manufacturers. 

5.6.4 Scaling of the Motor Losses Data 

 Once DOE generated a market picture of motor losses for each motor category, DOE 

developed an approach to scale the results of the three product classes analyzed in the 

engineering analysis. This meant scaling to the other 69 product classes for each efficiency 

level, or design, that DOE created. DOE normalized the motor losses of the market to 

EERE-2007-BT-STD-0007 COMMENT 33
5-32 

correspond to the value of the baseline efficiency level for the three representative product 

classes. For example, DOE compared the average motor losses of the market for a 1 

horsepower, four pole, polyphase motor to the motor losses of the baseline design DOE 

developed in the engineering analysis for that same motor. DOE found the percentage change in 

motor losses between those two motors and applied that same percentage change to the 

remaining product classes for polyphase motors, thus creating a baseline motor loss level for all 

polyphase product classes. This constituted a shift up in motor losses, but down in efficiency. 

After the initial shift down in efficiency, DOE incremented the aggregate market data by the 

percentage change seen from one efficiency level to the next. This constituted seven or eight 

shifts down in motor losses, but up in efficiency and resulted in comparable efficiency levels for 

all product classes at all efficiency levels, for a given motor category. 

5.6.5 CSCR Motor Scaling 

 The scaling methodology outlined above was utilized separately for polyphase and CSIR 

motors using product line data for each of those motor categories. For CSCR motors, however, 

there was not enough information available to identify efficiency relationships between product 

classes. This is because manufacturers do not currently make CSCR motors for all of the 

horsepower and pole configuration combinations that DOE uses to define its product classes. 

Currently, most manufacturers only make four pole CSCR motors, so DOE compared these four 

pole CSCR product lines to the manufacturer’s corresponding four pole CSIR product lines. 

DOE found that the relationships, or changes in efficiency relative to horsepower, appeared to be 

the same for both motor categories, but the efficiency of CSCR motors was shifted higher. This 

relationship can be seen in Figure 5.6.3. 

Figure 5.6.3. Four Pole CSIR Efficiency vs. Four Pole CSCR Efficiency 

 In light of the parallel efficiency relationship between CSCR and CSIR motors, and the 

fact that very limited CSCR motor data is available, DOE decided to base its CSCR efficiency 

scaling on available CSIR data. Thus, DOE utilized the same motor losses tables it used for 

EERE-2007-BT-STD-0007 COMMENT 33
5-33 

CSIR scaling when performing scaling for CSCR motors. However, rather than scaling based on 

the percentage change of the four pole 0.50 horsepower product class, as was done for the CSIR 

motors, DOE performed scaling based on the percentage change in the four pole 0.75 

horsepower product class, which was the representative product class analyzed for CSCR 

motors. 

EERE-2007-BT-STD-0007 COMMENT 33
5-34 

REFERENCES 

1

 Design Considerations to Optimize Stator Manufacturing, Alliance Winding Equipment, Inc., 

Ft. Wayne, Indiana. Blade-Gap Chart. 

2 U.S. Department of Labor, Bureau of Labor Statistics, Producer Price Indices. Last accessed April 

12, 2009. <http://www.bls.gov/ppi>.

3

 U.S. Census Bureau, 2002 Economic Census of Industry Series Reports for Industry, US 

Department of Commerce, 2003. 

EERE-2007-BT-STD-0007 COMMENT 33