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Electric Motor Efficiency under Variable Frequencies and Loadshttp://www.itrc.org/reports/pdf/r06004.pdf ITRC Report No. R 06-004

Electric Motor Efficiencyunder Variable Frequencies and Loads

October 2006

Prepared for

California State University Agricultural

Research Initiative

California Energy Commission Public

Interest Electric Research

United States Dept. of Interior

Bureau of Reclamation

by

Dr. Charles Burt, Dr. Xianshu Piao, Franklin Gaudi, Bryan Busch, and Dr. NFN Taufik

Irrigation Training and Research Center (ITRC)California Polytechnic State University (Cal Poly)

San Luis Obispo, CA 93407-0253

805-756-2379www.itrc.org


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Irrigation Training and Research Center - i - Electric Motor Efficiencyunder Variable Speeds and Loads

TABLE OF CONTENTS

Introduction ....................................................................................................................... 1Background ..................................................................................................................... 1

Procedures and Methods .................................................................................................. 5Motor Testing Configuration .......................................................................................... 5

Electrical supply.......................................................................................................... 5Motor test stand........................................................................................................... 6Motors ......................................................................................................................... 7Measurements ............................................................................................................. 7

RPM .................................................................................................................................... 8Torque ................................................................................................................................ 8Electric Power Characteristics .......................................................................................... 9

IEEE Standard 112-2004 ................................................................................................. 10On-going Quality Control ................................................................................................ 10

Results .............................................................................................................................. 11Power Factor ................................................................................................................. 11VFD Controller Efficiency ........................................................................................... 12Motor Efficiency ........................................................................................................... 14Air Conditioning Power Requirement .......................................................................... 17

Conclusions ...................................................................................................................... 18

References ........................................................................................................................ 20

LIST OF APPENDICES

Appendix A: Motor Operating and Testing ProcedureAppendix B: Motor Replacement ProcedureAppendix C: Sample Data Sheets

Appendix D: Equipment Descriptions


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Irrigation Training and Research Center - ii - Electric Motor Efficiencyunder Variable Speeds and Loads

LIST OF FIGURES

Figure 1. Induction motor efficiency as a function of load (Natural Resources Canada,2003) .................................................................................................................. 2

Figure 2. Induction motor power factor (PF) as a function of full-load amperage (NaturalResources Canada, 2003) ................................................................................... 3

Figure 3. Electrical supply for the motor testing ............................................................... 5Figure 4. Motor test stand. ................................................................................................. 6Figure 5. Data collection .................................................................................................... 8Figure 6. Pulse Width Modulation signal compared to sinusoidal .................................... 9Figure 7. Power Factor versus load.................................................................................. 11Figure 8. Power Factor versus motor output horsepower for all motors tested with

Danfoss VFD controller ................................................................................... 12Figure 9. VFD controller efficiency with various motors at 100% RPM and varying

loads ................................................................................................................. 13Figure 10. VFD controller efficiency with various motors at 40% RPM ........................ 13Figure 11. Efficiencies of all motors, across-the-line, at various relative loads .............. 14Figure 12. Motor efficiency at 10% RPM increments under various loads ..................... 15

LIST OF TABLES

Table 1. Full Load Motor Efficiencies at 1800 RPM (Motor Decisions Matter, 2003). ... 2Table 2. Idealized VFD Efficiency Factor (motor plus VFD controller) that ignores

motor duty-point movement (derived from Wallbom-Carlson, 1998) ............... 4Table 3. Motor Efficiencies with VFD control (derived from Rooks and Wallace, 2003) 4Table 4. Motors used in testing and their nameplate specifications .................................. 7Table 5. Load cell locations on pivot arm for measuring torque ....................................... 9Table 6. Relative motor efficiencies with and without VFD control ............................... 16


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Irrigation Training and Research Center - 1 - Electric Motor Efficiencyunder Variable Speeds and Loads

INTRODUCTION

The Irrigation Training and Research Center (ITRC) of California Polytechnic StateUniversity (Cal Poly), San Luis Obispo, completed this study on the behalf of the

California State University Agricultural Research Initiative project No. 05-3-009.Funding was also provided by the California Energy Commission Public Interest ElectricResearch (PIER) program, Agreement No. 400-99-014, and the US Bureau ofReclamation Grant No. 04FG210013.

The primary research objective of this study was to determine motor efficiencies undervarying speeds (induced by a VFD controller) and loads. A broader objective was toprovide sufficient information to designers and economists so that they could estimatetotal pumping plant power usage with a VFD-controlled installation. Motors were testedwith VFDs as well as across-the-line. This study found that, on the average, the relativeefficiency of the electrical system with a VFD may be about 8% lower than the relative

efficiency of a properly designed, full-load across-the-line system.

Background

Electric-powered pumping by irrigation districts and farmers in the U.S. represents amajor consumption of electricity. It is estimated (Burt et al, 2003) that the annualagricultural electric pumping usage in California is approximately 10 million MWh/hr.Variable frequency drive-controlled motors have been used in many irrigationapplications in attempts to save energy (ITRC, 2002) and/or to improve control inpipelines or canals (Burt and Piao, 2002).

Economic tradeoff analyses for comparison of Variable Frequency Drive (VFD) -controlled versus conventional single-speed motor applications for pumps requireknowledge of how the efficiencies of the pump, motor, and VFD controller change as thepump flow rate or head changes. The annual energy cost is computed by knowing thehours of operation at various flow rates, the overall pumping plant efficiency at each flowrate, and the cost of power.

The procedures for combining pump curves at various speeds with irrigation systemcurves to determine pump efficiencies are well understood. Some pump companies suchas ITT Goulds provide software that combines user-specified system curves at variousRevolutions per Minute (RPM) for user-specified pumps (Goulds, 2003).

Nominal full load efficiency standards for polyphase induction motors of various sizeshave been specified by the US Energy Policy Act of 1992. Those standards apply to allmotors manufactured after October 1997. Motor Decisions Matter (2003), an industrygroup dedicated to improving motor application efficiencies, developed Table 1forcomparison.


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Table 1. Full Load Motor Efficiencies at 1800 RPM (Motor Decisions Matter, 2003).

Size (hp)Pre-

EPActaEPActb

NEMAPremiumc

1.0 76.7 82.5 85.5

1.5 79.1 84.0 86.5

2.0 80.8 84.0 86.53.0 81.4 87.5 89.5

5.0 83.3 87.5 89.5

7.5 85.5 89.5 91.7

10.0 85.7 89.5 91.7

15.0 86.6 91.0 92.4

20.0 88.5 91.0 93.0

25.0 89.3 92.4 93.6

30.0 89.6 92.4 93.6

40.0 90.2 93.0 94.1

50.0 91.3 93.0 94.5

60.0 91.8 93.6 95.0

75.0 91.7 94.1 95.4100.0 92.3 94.5 95.4

125.0 92.2 94.5 95.4

150.0 93.0 95.0 95.8

200.0 93.5 95.0 96.2

a. Pre-EPAct: DOEs MotorMaster+ software version 4.00.01 (9/26/2003) AverageStandard Efficiency motor defaults

b. EPAct: Energy Policy Act of 1992c. NEMA Premium: NEMA MG 1-2003 Table 12-12

Motor efficiency standards for other 2, 4, 6, and 8 pole motors can be found in Douglass(2005). For comparison, EPAct efficiency standards for 20 HP motors with Open Drip

Proof (ODP) enclosures are 90.2%, 91.0%, 91.0%, and 90.2% for synchronous speeds of3600, 1800, 1200, and 900 RPM, respectively.

Motor efficiencies at a constant RPM will change as the load changes. The efficiency ofa typical motor may peak at about 75% load, but it will drop rapidly below somethreshold. Figure 1shows the approximate relationship for premium efficiency motors.

Figure 1. Induction motor efficiency as a function of load (Natural Resources Canada,

2003)


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Wallace et al (2002) examined the efficiencies of three motors (50 HP, 100 HP, and 200HP) from each of seven manufacturers over a range (25% to 120%) of loads all at therated RPM of 1800. At 25%, the efficiencies variations (high/low) were 94.9/90.9,94.8/90.0, and 93.7/89.6 for 200, 100, and 50 HP motors, respectively.

The power factor (PF) of a motor at a constant RPM will also change as the load changes.Power factors listed in the Department of Energys MotorMaster+ software (DOE 2005)vary widely among manufacturers, as did the efficiencies determined by Wallace et al(2002). However, Figure 2provides a general illustration of how the PF varies withload.

Figure 2. Induction motor power factor (PF) as a function of full-load amperage (Natural

Resources Canada, 2003)

For designers considering variable frequency drive (VFD) applications, importantquestions are:

(i) Will the relationships seen in Figures 1 and 2 change with the introduction ofthe VFD?

(ii) Are there other losses that must be considered when computing the powerrequirement (quantity and quality) of a VFD installation?

A literature search indicates that when the economics of a VFD installation are computed,a variety of approaches for assuming motor efficiency have been used. The IAC (2006)computations assume a full-load motor efficiency at all speeds and loads. Rishel (2003)notes that considering the thousands of variable-speed motors that are installed eachyear, it is the writers opinion that an independent organization such as NEMA or IEEEshould develop a program for determining the estimated efficiencies of induction motors

at reduced speeds and loads ..

There have been difficulties in accurately measuring the efficiency of a motor controlledby a variable speed drive. Nailan (2002) notes that in the 1980s an IEEE WorkingGroup attempted to write a standard procedure for determining the efficiency of inductionmotors in VFD systems an attempt that was abandoned at least in part because oftechnical difficulties. He also notes that conventional equipment for measuring input


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power is subject to error of unpredictable magnitude when nonsinusoidal current andvoltage are being monitored.

Wallbom-Carlson (1998) proposed an efficiency factor that includes losses from the VFDitself, losses generated in the motor by the VFD, and losses in the motor due to the motor

duty-point movement. He presented a theory of how a VFD Efficiency Factor(neglecting motor duty-point movement) would vary as a function of relative frequency.Estimates based on his proposal are seen in Table 2. The hypothesis was that:

Overall electrical efficiency = (VFD Factor) (Motor efficiency at 100% speed at specified load)

Table 2. Idealized VFD Efficiency Factor (motor plus VFD controller) that ignoresmotor duty-point movement (derived from Wallbom-Carlson, 1998)

% of Rated MotorFrequency

VFDEfficiency

Factor

100 .97

90 .94580 .9270 .9060 .87550 .8540 .825

Rooks and Wallace (2003) provided data from an unspecified motor manufacturer thatwas used with several assumptions to estimate the information shown in Table 3.

Table 3. Motor Efficiencies with VFD control (derived from Rooks and Wallace, 2003)

Nameplate RatedHP at 60 Hz

Motor Efficiency at Various Relative Speeds (RS) and RelativeLoads (RL)

RS/RL

100/80 75/34 50/10

50 94.9 94.1 84.5100 96.0 93.7 87.0200 96.4 93.8 86.0


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PROCEDURES AND METHODS

Motor Testing Configuration

Donations were received from Emerson Motor Company (75, 50, and 20 HP premiumefficiency motors), Thoma Electric of San Luis Obispo (technical assistance for theelectrical installation), Pacific Gas and Electric Co. (pressure gauges), and BranomInstrument Co. of Sacramento (Danfoss VFD controller). A detailed description of themotor testing equipment and setup can be found in Appendix D. The motor testingconfiguration at the Water Delivery Facility on the Cal Poly campus consisted of:

1.

Electrical supply2. Motor test stand3. Motors4. Data

Electrical supply

The electrical supply was configured to operate motors across-the-line (ATL) or via a100 HP Danfoss VLT 8000 AQUA VFD controller (Figure 3). The configuration alsoincluded a Kooltronic RP52 14,000 BTU Air Conditioner connected to the VFDaluminum enclosure. Motor operating and testing procedure descriptions can be found inAppendix A. Detailed procedures for installing and disconnecting the electrical supplyequipment are included in Appendix B.

Figure 3. Electrical supply for the motor testing


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Motor test stand

The motor was bolted on a machined rotating base plate (Figure 4). The torquedeveloped by the motor was measured (Honeywell Model IC48 150 lb range Load Cell)by sensing the tension created by a long base plate arm extension at a specific distance

from the center of the motor. The load on the vertical pump shaft was created by aDenison Hydraulics goldcup series P7P closed circuit piston pump.

Figure 4. Motor test stand.

The load creator (hydraulic pump) was designed and fabricated with the followingcriteria:

a. Adapt to different motor shaft sizes (lengths and diameters).b. Create a constant load anywhere between 1 HP and 100 HP.c. Create a torque ranging from 25 to 500 ft-lbs.

Water to cool the hydraulic oil was filtered by three 36 sand media tanks andpumped through a BPS-70-125 brazed plate cooler manufactured by ThermaSysCorporation.


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Motors

Twelve 60 Hz, 460V ODP vertical hollowshaft motors were tested. Table 4provides thenameplate specifications.

Table 4. Motors used in testing and their nameplate specifications

ITRC ID Manuf. Nom HPNom.RPM PF EFI Amps Other

AO1 US 20 1765 85.6 87.5 24.3 VFD rated

AO2 GE 20 1175 85 91 24.1

AO3 US 20 1770 85.4 92.4 23.7 Premium

AO5 US 75 1780 85.3 95 87 Premium

AO6 GE 100 1780 ns 91 124

AO9 US 40 1780 85.7 88.5 49

AO10 GE 75 1785 85 95 87.1

AO11 GE 50 1775 ns ns 61.1

AO12 US 50 1780 87.5 94.5 56 Premium

AO13 US 40 3515 89.5 90.2 46

AO14 US 75 895 74.3 94.1 100

AO15 GE 50 1185 ns 91.7 61.2

Notes: ns = not stated on the nameplateGE = General ElectricUS = US Motors or Emerson

Measurements

During each test, measurements were made of the following data:a. RPM of the motor

b.

Torque developed by the motor, which consisted of:i. The lever arm at which a force was measured

ii. The force developedc. Electric power characteristics before and after the VFD or ATL panel

Sample data sheets can be found in Appendix C. An overview of themeasurements is provided in Figure 5.


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Figure 5. Data collection

Data were automatically logged on two laptop computers (LT21 and LT11).Redundant data and some trial observations were manually logged. The LT11computer was programmed with National Instruments Lookout HMI software todisplay and log the data.

RPM

A Monarch Instruments ACT-2A Panel Tachometer was used to measure themotor shaft RPM, with values downloaded to Lookout. Readings from a hand-held Extech Instruments Combination Photo Tachometer/Stroboscope (Model461825) that used reflective tape on the shaft were also taken. As long as the tworeadings were close (within ~5 RPM), the Lookout reading was recorded.

Torque

The load cell was placed at one of five locations (Table 5), each measured within+/- 0.1 mm. The calibration of the load cell was checked at the beginning and endof each test set using standardized weights. Determining the proper way to mountand calibrate the load cell to obtain the correct horizontal force reading was one ofthe most challenging aspects of this project. Problems with vibrations, impactforces, and vertical forces due to the weight of the torque arm were all overcome.


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The torque was calculated as:

Ft-lb of torque = Distance Force

The output Horsepower of the motor was then computed as:

Output Horsepower = (Ft-lb of torque) (RPM/5,252)

Table 5. Load cell locations on pivot arm for measuring torque

Average Distances Between Points

Center to 1stCenter to

2nd

Center to

3rd

Center to

4th

Center to

5th

Feet 1.036 2.023 3.013 4.017 5.020

Mm 315.7 616.6 918.4 1224.3 1530.0

Electric Power Characteristics

This research measured both the efficiency of the VFD controller and theefficiency of the motor. Therefore, it was necessary to measure the electric powerbetween the VFD controller and the motor. The wave forms of input to a VFDcontroller are sinusoidal, while the output wave forms are not. The controlleroutput wave forms are chopped DC pulses that mimic an AC sinusoid characteristic of a Pulse Width Modulation (PWM) VFD controller. The signalfrom a PWM-type VFD overlaid on a sinusoidal signal is shown in Figure 6.

Figure 6. Pulse Width Modulation signal compared to sinusoidal

Because of the nature of the output wave form, special electronic measurementequipment was needed. A Yokogawa/GMW Danfysik Ultrastab 866RMultichannel Current Transducer System provided 6 transducers (one for eachphase in and out of the VFD) with power and signal conditioning.

Data from the Current Transducer System was then fed into a Yokogawa WT1600Digital Power Meter and Communication Interface. The signals from theYokogawa power meter were processed in a laptop computer (LT21) that wasconfigured with LabView Real-time Module software. This processed data wasthen passed from laptop LT21 to LT11, where the data was logged and displayedin Lookout.


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The electric power data collected were:

Amperage on each phase before and after the VFD

Voltage on each phase before and after the VFD

VFD frequency

Active Power before and after the VFD

Apparent Power before and after the VFD Power Factor

IEEE Standard 112-2004

The Institute of Electrical and Electronics Engineers (IEEE) developed IEEE Std112-2004 for testing polyphase electric induction motors. Specifically, EfficiencyTest Method B covers the type of procedure used in this research. Many portionsof this test standard are used if one wants to separate the components (friction andwindage, core, stator, and rotor) of motor losses. It also provides computationalprocedures for correction factors for stray-load, non-standard temperatures, andother factors. The procedures used in this research did not have a goal of

identifying the component losses, and did not apply the IEEE Std 112-2004corrections because they were judged to have an insignificant impact on theconclusions of this research project.

On-going Quality Control

On-going quality control of data was maintained by frequent calibration of theload cell, redundant measurements of the motor RPM, and the use of high qualityelectric power measurement equipment. Each motor was run continuously for aminimum of 12 hours immediately before any measurements were made. Tofurther check for errors, the full set of tests was duplicated for each motor on thesame day, after completion of the first set of tests.


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RESULTS

Power Factor

The curves in Figure 7show how the Power Factor varies with load when a motor isoperated across-the-line (ATL). The Figure 7 curves somewhat resemble thedimensionless curves seen in Figure 2 from Natural Resources Canada (2003).

Figure 7. Power Factor versus load

The important point from Figure 7is that when operated with this particular VFDcontroller, the power factor is simply a function of the applied load, regardless of thenominal horsepower or nominal speed of the motor. This is highlighted in Figure 8.Figure 8also shows that the lowest power factor measured was 0.65, which isconsiderably higher than the lowest power factors measured with across-the-lineconditions at low output horsepowers. Because only one VFD controller was used, it isimpossible to say how other VFD controllers would influence the PF.


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Figure 8. Power Factor versus motor output horsepower for all motors tested with Danfoss

VFD controller

VFD Controller Efficiency

The efficiency of the VFD controller was found to depend somewhat on the particularmotor that was tested. In particular, the VFD efficiency when testing the 900 RPM(nominal) 75 HP motor averaged about 1% lower efficiency than with the 1200, 1800,and 3600 RPM (nominal) motors.

Figures 9 and 10show VFD efficiencies at two RPMs and various Load Factors. Otherefficiencies were measured at increments of 10% nominal RPM, with similar results.These results coincide with the claims of high efficiency given by manufacturers of highquality, recent designs of VFD controllers. The efficiency does drop somewhat at verylow loads, but in no case did it fall below 95%.


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Figure 9. VFD controller efficiency with various motors at 100% RPM and varying loads

Figure 10. VFD controller efficiency with various motors at 40% RPM


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Motor Efficiency

Figure 11depicts motor efficiencies for across-the-line operation. It is clear that thereare differences between individual motors. The lowest efficiency is from a 20 HP USMotors motor (A01) that is designated as suitable for a VFD, and the highest efficiency isfrom another 20 HP US Motors motor (A03) that is designated as a Premium motor.

Four of the motors (A02, A03, A05, and A09) maintained a very high efficiency (close to95%) across the span of relative loading.

Figure 11. Efficiencies of all motors, across-the-line, at various relative loads

Figure 12shows the performance of motors under various relative loads, at differentRPMs including a repeat of Figure 11in the upper left-hand corner for scalecomparison.


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Figure 12. Motor efficiency at 10% RPM increments under various loads


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A fundamental question is whether motor efficiencies stay the same if the motor issubjected to various loads when across-the-line, as compared to when the electric powercomes through a VFD controller. Table 6shows the pertinent values from the testing.The answers appear to be:

1.

On the average, there is no apparent difference.2. For an individual motor, differences as large as 18% were observed.3. Relative motor efficiencies can be higher or lower with a VFD.4. There appears to be more variation in performance between motors as the

relative loads and relative RPMs decrease.5. At 100% relative RPM, there was no more than a +/- 5% difference in motor

efficiency.

Table 6. Relative motor efficiencies with and without VFD control

Ratio of VFD/ATL

Rel.

RPM

Rel.

Load

Avg. Min. Max.

40 0.2 0.99 0.86 1.10

60 0.2 1 0.87 1.18

60 0.4 0.96 0.9 1.03

100 0.2 - 1.0 0.99 0.94 1.04

Notes:VFD/ATL = Relative motor efficiency

= (motor efficiency with VFD control)/(motor efficiency across-the-line)Rel. Load = The relative load placed on the motor. For example, a relative load of 0.4 on

an 80 HP motor equals 0.4 80 HP = 32 HP.Rel. RPM = The relative RPM. For example, a relative RPM of 60 on an 1800 RPM

motor equals 0.6 1800 RPM = 1080 RPM.Avg. = The average value of all tests with this combination of relative RPMs and Loads.

Min. = The minimum value of all tests with this combination.Max = The maximum value of all tests with this combination.

There was no noticeable difference between premium and standard motors, regardingtheir relative efficiencies at different relative RPMs and Relative Loads.


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Air Conditioning Power Requirement

Variable frequency drive controllers generate heat through their inefficiencies. Althoughthe inefficiency may be small, 3-5% - 3% of a 100 HP unit represents 3 HP of heat thatmust be dissipated. Air conditioning (AC) units either directly mounted to the VFD

panel, or constructed to cool the entire motor control center building are standardpractice for irrigation applications.

None of the extensive literature that was examined regarding VFD efficiency made anymention of the additional power required for air conditioning. This research project didnot examine the details of AC power requirements. Depending upon the heat released,ambient temperature, and AC design, the power requirement will vary. The authorssuggest that if the VFD controller is 97% efficient, the additional power requirement forthe AC unit can be estimated as:

(100% - 97%) 2 Input HP

For example, for a Full Load input of 110 HP to a VFD controller that operates at 97%efficiency, the additional power requirement at Full Load would be:

Additional Power = 3% 2 110 HP = 6.6 HP


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CONCLUSIONS

The results of this research lead to the following conclusions that appear to be eitherunknown or little advertised:

1. Commercially available variable frequency drive (VFD) controllers are availablethat provide significant improvement of the Power Factor of motors, whencompared to across-the-line applications.

2. The efficiency of a VFD controller appears to be slightly impacted by the motorthat it is controlling.

3. The following can be stated for the average condition when a motor is subjectedto varying loads: The efficiencies of a motor that is operated by a VFD controllerwill be about the same as the efficiency of a motor that is operated across the line.However, some motors operate with either a higher or lower relative efficiencywhile being controlled by a VFD controller instead of operating across-the-line.

4. The additional power requirement of an air conditioner for the VFD controllermust be considered when determining the total power requirement for the unit andthe initial and annual costs.

The data from this research confirm the following frequently noted points:

1. Commercially available VFD controllers maintain high efficiencies acrosspractical ranges of loads and frequencies.

2. Efficiency computations for induction motors that operate under varying loadsmust consider the significant change in motor efficiency that can occur as the load

changes. In particular, motor efficiencies can drop by about 10% as the relativeload drops from 60% to 20%. The changes in motor efficiencies as the relativeload varies from 100% to 60% are relatively minor.

3. When working above relative loads of 40%, the inherent efficiency of the motoritself is more important than the variation in efficiency due to changing loads.

In summary, on the average, the relative efficiency of the electrical system with a VFDmay be about 8% lower than the relative efficiency of a properly designed, full-loadacross-the-line system. This 8% value assumes:

- No change in motor efficiency

-

A 3% loss in efficiency through the VFD controller-

A parallel 5% additional power requirement for the air conditioner

The 8% is a number that has not historically been available. At first glance, it appearsthat VFD-controlled applications may not be economical if there is a drop of 8%efficiency. However, the 8% is only part of the story. The 8% assumes that the across-the-line system was truly properly designed. A system with a VFD can adjust for errors,


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but an across-the-line system cannot adjust for errors in estimations of total head or flowrate requirements.

Furthermore, the electric system efficiency is only one part of the overall electricpumping system. To determine the relative efficiency of an overall electric pumping

system, one must also account for the changing pump efficiency over time and atdifferent operating points, and the ability of a VFD-controlled system to reduce the totalpressure or flow requirement when needed. This research project did not examine thosebenefits, although they have been well documented by ITRC and others. In addition, formany irrigation pumping applications the improved control of pressures or flows is thedominant benefit rather than power savings.


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REFERENCES

Burt, C.M. and X. Piao. 2002. Advances in PLC-Based Canal Automation.Proceedingsof the United States Committee on Irrigation and Drainage Conference on

Energy, Climate Environment and Water Issues and Opportunities for Irrigation andDrainage. Held in San Luis Obispo, CA. July 9-12. pp. 409-422.

Burt, C.M., D.J. Howes, and G. Wilson. 2003. California Agricultural Water ElectricalEnergy Requirements. ITRC Report No. R 03-006. Prepared for the Public InterestElectric Research program of the California Energy Commission. Irrigation Training andResearch Center. California Polytechnic State University. San Luis Obispo, CA. 154pages.

DOE. Department of Energy. 2005. MotorMaster+(Version 4) software.

Douglass, J. 2005 (updated). Induction Motor Efficiency Standards. Washington StateUniversity Extension Energy Program. WSUEEP02_029. 8 pg.

Goulds. 2003. Turbine Pump Selection, Version 7.1. Developed for Goulds PumpTurbine (ITT Industries) by Engineered Software, Inc. Lacey, WA 98503-5941

IAC. 2006. Electric Motor Systems. Industrial Assessment Center. Center for EnergyEfficiency and Renewable Energy. Univ. of Mass., Amherst.

ITRC. 2002. Variable Frequency Drives and SCADA Are They WorthwhileInvestments? ITRC Report No. R 02-006. Irrigation Training and Research Center.California Polytechnic State University. San Luis Obispo, CA. 10 pages.

Motor Decisions Matter. 2003. Efficiency Values Used to Estimate Annual EnergySavings (Spreadsheet). 1-2-3 Approach to Motor Management.

Nailan, R.L. 2002. Just How Important is Drive Motor Efficiency? ElectricalApparatus. Barker Publications, Inc. Chicago, IL. March issue.

Natural Resources Canada. 2003. Technical Fact Sheet Premium-Efficiency Motors.Cat. No. M144-21/2003E; ISBN 0-662-35668-3. Office of Energy Efficiency. EnergyInnovators Initiative. Ottawa, ON. Canada.

Rishel, J.B. 2003. How to Calculate Motor Efficiency for Variable Speed CentrifugalPumps. Engineered Systems. August issue.


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Rooks, J.A. and A.K. Wallace. 2003. Energy Efficiency of Variable Speed DriveSystems. Pulp and Paper Industry Technical Conference, Conference Record of the2003 Annual. 16-20 June. Pg. 160-163.

Wallace, A.K., J. A. Rooks, and J. R. Holmquist. 2002. Comparison Testing of IEEE

Standard 841 Motors. IEEE Transaction on Industry Applications. 38(3):763-768.

Wallbom-Carlson, A. 1998. Energy Comparison. VFD vs. On-Off ControlledPumping Stations. Scientific Impeller. ITT Flygt AB, Sweden. Pg. 29-32.


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Irrigation Training and Research Center Electric Motor Efficiencyunder Variable Speeds and Loads

APPENDIX A

Motor Operating and Testing Procedure


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Irrigation Training and Research Center A-1 Electric Motor Efficiencyunder Variable Speeds and Loads

Appendix A: Motor Operating and Testing Procedure

1.0. Water Flow

1.1.

Valve Position

1.1.1.Find valve shown in inset of Figure A-1, below.

Figure A-1. Water source location

1.1.2.Turn valve counterclockwise (open).

1.2. Filter Operation

1.2.1. Check that the pressure of the media filter discharge is about 15 psi or greater(see Figure A-2, inset).

1.2.2.The backflush controller should be on.

1.2.3.The pressure differential switch should be set to 3 psi.

1.2.4.

The elapsed time switch should be set to 4 hours.

1.2.5.

The pressure differential gauge (located inside the filter control box, behind thepanel) should read less than 3 psi; otherwise, the filter should be backflushed.

mediafilters


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Figure A-2. Media filter with pressure gauge behind the solar panel

1.2.6. Once you believe you have started the water and filters, make sure water iscoming out of the PVC pipes shown in Figure A-3. DO NOTput a load on themotor unless water is coming out of the pipes.

Figure A-3. Water exit location


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2.0. Confirm Electrical System Settings

2.1. The Main Disconnect (Panel 1) and the 120V Main (Box 6) are usually leftON.

2.2. Everything else should be OFF.

Figure A-4. Electrical panels for motor testing

3.0. VFD Setup

3.1. Power up the VFD

3.1.1.

Verify that the Main Disconnect (Panel 1) isON.

3.1.2. Verify that the 120V Main (Panel 6) is ON.

3.1.3. Open Panel 9, 120 V Breaker, and turn on theVFD air conditioner (Unit 7).

3.1.4. Switch VFD Input (Panel 2) to the vertical up

position, To VFD. It takes a few moments forthe VFD Controller (Unit 8) to come online.

3.1.5. Leave VFD Output (Panel 3) in the horizontalOFF position.

3.2. Adjust Motor-Specific Settings

3.2.1. Refer to Figure A-5 (right) for button locationson VFD control panel.

VFDVFD

Input

VFDOutput

SCADAPack

PLC & Meters

Main

Disconnect

1

Across-the-Line

Motor Starter

6

120V

Main

FromVFD

Cable from the motor test platform

2

3 48 7

From

manual

5

From

VFD

Frommanual

9

120V

Breaker

Box

Figure A-5. VFD control

panel


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3.2.2.Press QUICK MENU button to access settings.

3.2.3.Press + and - buttons to cycle through settings.

3.2.4. Verify each setting with that listed on the motor nameplate.

3.2.5.

To change a setting, press the CHANGEDATA button.

3.2.5.1. Press the + and - buttons to change the values for that setting.

3.2.5.2. Press OK button when done.

3.2.6. After changing any setting, use the + and - buttons to cycle through allsettings and confirm they are all correct. (A change in one value could affectother values.)

3.3. Prepare VFD for Motor Startup

3.3.1.Press HAND START button

3.3.2.Use the + and - buttons to set the speed to 40%.

3.3.3.Press the OFF STOP button.

4.0. VFD - Motor Startup

4.1. Confirm that the flow control valve is all the way down (closed). Refer toFigure A-6, below, for location.

4.2. Confirm that the pressure control valve is all the way up (closed). Refer toFigure A-6, below, for location.

4.3. Turn VFD Output (Panel 3) to the From VFD (vertical up) position.

4.4.

Return to the VFD Controller (Unit 8) and press the Hand Start button.

(The motor should start spinning at 40% of its rated RPM. If the motor fails to start,refer to Appendix B: Motor Replacement Procedure, Section 8.0, Motor Start Testand contact Bryan Busch to help troubleshoot the problem.)


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Figure A-6. Motor station setup

5.0. Motor Warmup

5.1. At all times, the pressure indicated by the low pressure gauge should neverexceed 450 psi.

5.2. On the VFD Controller, press the HAND START button, then press and

hold the + button to increase the motor speed to 100% of its rated RPM.5.3. Open the Flow Control Valve by pressing the red button in the middle of the

control knob while lifting the control knob.

5.4. Open the Pressure Control Valve by turning the knob clockwise until the HighPressure Gauge reads 1000 psi.

5.5.

Allow the motor to warm up for approximately twelve hours (overnight)before beginning any motor tests. The two tests for each motor should takeplace back-to-back the following morning.

6.0. Computer Startup6.1. ITRC Laptop 21 (LabVIEW installed)

6.1.1.Connections

6.1.1.1. The 9pin-RS232 from the back of the Yokogawa to the COM1 port of

LT21.


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6.1.1.2. The USB cable (blue) from SCADAPack COM1 Port connects to the

lower USB port at the back of LT21.

6.1.2.User name = xpiao; Password = itrc.

6.1.3.Verify network connections

6.1.3.1.

Go to Start > Programs > National Instruments > NI-Serial >Troubleshooting Wizard (or double click the desktop shortcut labeled

Troubleshooting Wizard).

6.1.3.2. The test will start automatically, and upon completion a text box will

appear stating that the test is completed. Press OK.

6.1.3.3. If the test is unsuccessful unplug the USB cable from the back of the

computer and plug it back in again. Press Reset in the

Troubleshooting Wizard box to run the test again.

6.1.4.Run Yokogawa WT1600 Driver

6.1.4.1. Go to Start > Programs >National Instruments > LabVIEW 7.1 >

LabVIEW (or double click the desktop shortcut labeled LabVIEW).

6.1.4.2. It will take about 1-2 minutes to start up and begin running. At this

point, the Active and Apparent Powers 1 through 6 and the Voltage

and Amps 1 through 6 should update automatically.

6.1.4.3. At the top of the screen are stop and start buttons, represented by a right

arrow and red circle, respectively. These can be used to run or stop the

driver if needed.

6.2. ITRC Laptop 11 (Lookout installed)

6.2.1. Connections

6.2.1.1. The USB plug (gray) from the SCADAPack COM2 Port to on the lower

USB port at the back of LT11.6.2.2. User name = itrc; Password = itrc

6.2.3. Lookout should start automatically after booting up the computer. If not, go toStart > Programs > National Instruments > Lookout 5.0. The overview screenwill appear.

Data displayed on this overview screen is a running average over the

previous minute. Therefore it is recommended to wait two (2) minutes after

making a change to the system before recording results.

6.3. If using other computers, view Software Installation, Section 19.0, at the endof this manual.

7.0. Load Cell Calibration

7.1.

Load Cell Setup

7.1.1.Secure the load cell to the bottom of the support arm.

7.1.2.Plug the data transfer cable into the load cell.


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7.1.3. Secure the five (5) pound weights (#1-5) to the bottom of the load cell. Refer toFigure A-7, below, for setup.

Figure A-7. Load cell calibration setup

7.1.4.In cabinet #4, (SCADAPack, PLC & Meters) close the main circuit.

7.1.4.1. Always open this circuit before unplugging the data transfer cable from

the load cell.

7.2. Calibration Recordings

7.2.1.

Using a load cell calibration sheet (example sheet can be found in Appendix C),record the force displayed on the overview screen in Lookout and the forcedisplayed on the SCADAPack screen for weights #1-5.

7.2.2. Add weights #6-10 one at a time and record the forces after each addition.

7.2.3. Remove weights #10-6 one at a time and record the forces after each removal.

7.2.4.

Remove weights #1-5 and record the final force (without any weights).

7.2.5. Verify that the numbers are accurate. If they are not, contact Bryan Busch to helptroubleshoot the problem.

7.2.6. Record the air temperature by the motor during the calibrations and the time ofthe calibrations.

8.0. VFD Testing

8.1. Secure the load cell in the proper location.

8.1.1. Use the VFD Motor Test Sheet (example sheet found in Appendix C) todetermine in which location the load cell should be positioned.

load cellstoragelocation

weights#6-10

weights#1-5

load cell

(connected tometal arm)


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8.2. Click the Data Entry & Review button on the overview screen in Lookouton Laptop 11. The data set/view screen will pop up.

8.2.1.

Do not change the pre-set sensor calibration constants.

8.2.2. The Reset Data? switch should be left on No.

8.2.3.

Enter a Log File Name in the format Data_(month)(DD)(YY) (example:Data_Jan0106).

8.2.4. Enter the motor specifications, which can be found on the motor name plate (PF= Power Factor, EFI = Efficiency).

8.2.5. Under LC Type, enter 0 for the type of load cell used (0 = 150 lbs).

8.2.6. Enter the Load Cell Arm Location in Ft according to the location where theload cell is installed.

8.2.7.

Click the Overview button to return to the overview screen.

8.3. Adjust Motor Speed

8.3.1.

Always close the flow control and pressure control valves to remove the appliedload from the motor before adjusting the motor speed.

8.3.2. On the VFD Controller (Cabinet 8), press the HAND START button, then usethe + and - buttons to set the speed to that indicated on the VFD Motor TestSheet for the test you are running.

8.3.3. Press the DISPLAY MODE button twice and the + button once to displaythe current drawn by the motor.

At no time should you apply a load to the motor such that the current drawnexceeds the motors maximum amperage rating indicated on the motor name

plate.

8.4.

Adjust the Applied Load.8.4.1. Open the Flow Control Valve by pressing the red button in the middle of the

control knob while lifting the control knob.

8.4.2. Open the Pressure Control Valve by turning the knob clockwise until the valueindicated by the Sensotec A/D converter is nearly equal to the value calculatedfor the desired force.

8.4.3. Check the VFD display to confirm that the motors maximum amperage has notbeen exceeded.

8.4.3.1. If the maximum amperage has been exceeded, then back off on the

applied load until the motor is drawing its maximum amperage.

8.4.3.2.

Circle this amperage value on the datasheet to indicate that no furthertests at this speed are to be conducted.

8.5. Verify Applied Load

8.5.1. Wait at least one minute since the last adjustment to the system.

8.5.2. Confirm that the force displayed on the overview screen in Lookout isapproximately equal to the desired force indicated on the datasheet.


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8.5.2.1. If the displayed force is significantly different than the desired force then

adjust the pressure control valve accordingly.

8.6. Handheld RPM Measurement

8.6.1.

A piece of reflective tape has been applied to the collar joining the bottom of themotor shaft to the top of the pump shaft.

8.6.2. Carefully stand between the motor and the edge of the platform.

8.6.3. Without touching the motor or the testing stand, hold the tachometer 2-3 inchesfrom the motor in the opening shown in Figure A-8, below.

Figure A-8. Tachometer reading location

8.6.4. Press and hold the button on the top right side of the tachometer until the reading

stabilizes.

8.6.5. If the reading fails to stabilize, or stabilizes at a value out of line with the motorspecifications, then turn the sensor slightly to the left (so that it is notperpendicular to the shaft). Verify that the reading is within 5 RPM of the valueshown on the SCADAPack display.

8.7. Record Data

8.7.1. Fill in all pertinent data on the datasheet (example sheet can be found inAppendix C).

8.7.2.

Allow approximately two (2) minutes since the last adjustment to the systembefore logging data.

8.7.3.

On the Overview screen in Lookout, click the Log Data button.

8.7.4. Record the clock time of Laptop 11 on the data sheet for each test.

8.8. Repeat Steps 8.3. through 8.7. until all VFD tests are complete.

Remember to change the Load Cell Location on the Data Setup & Reviewscreen (Step 8.2.6.) whenever you move the load cell to a different position.


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9.0. VFD-Motor Shutdown

9.1. Remove the load from the motor by closing the flow control and pressurecontrol valves.

9.2.

Reduce VFD Speed.

9.2.1.On the VFD Control Panel, press HAND START button.

9.2.2.

Use the - button to set the speed to 40%.

9.2.3.Press the OFF STOP button.

9.3. Shut down VFD.

9.3.1.Pull the switches on Panels 2 & 3 to the horizontal OFF positions.

10.0. Across-The-Line Motor Startup

10.1.

Verify that the flow control and pressure control valves are closed. There isno load applied to the motor.

10.2. Attach a bungee cord to the arm of the test stand. (This takes the impact of thestart off of the load cell.) Refer to Figure A-9, below. Pull the switches onPanels 2 & 3 to the vertical-down ATL positions.

10.3. Lift the breaker handle of the Across-The-Line motor starter to the ONposition.

10.4. Turn the HOA switch on the side of the Across-The-Line motor starter to theHand position.

10.5.

Press and release the ON button.

10.6. Remove the bungee cord

Figure A-9. Bungee location for ATL startup


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11.0. ATL Testing

11.1. Follow steps 8.4. to 8.7. until all ATL tests are complete.

Remember to change the Load Cell Location (step 8.2.6.) whenever you move

the load cell to a different position.

12.0. ATL Motor Shutdown

12.1. Remove the load from the motor by closing the flow control and pressurecontrol valves.

12.2. On the ATL Motor Starter, turn the HOA switch to OFF.

12.3. Pull the switches on Panels 2 & 3 to the horizontal OFF positions.

13.0. Second Motor Test

13.1.

Repeat the motor testing procedure (Steps 7-12), recording the data on a new,identical data sheet.

13.1.1. Data from the computer can continue to be collected in the same folder.

14.0. Post-test Load Cell Calibration

14.1. Repeat step 7.0.

14.1.1. Calibrations will occur three times for each motor: before the first test, between

the two tests, and after the second test.

15.0. Computer Shutdown15.1. Laptop 21

15.1.1. Close the program LabVIEW.

15.1.2. Shut down Laptop 21.

15.2. Laptop 11

15.2.1.

Close the program Lookout.

15.2.2. Save data file to memory stick. File location:C:/ProgramFiles/National_Instruments/Lookout5.0/2006/(month)

15.2.3. Shut down Laptop 11.

16.0. General Cleanup

16.1. Return the computers to Cabinet 4.

16.2. Remove the Load Cell and return it to the gray box shown in Figures 6 & 7.

16.3. The Main Disconnect (Panel 1) and the 120V Main (Box 6) may be left ON.Everything else should be OFF.


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16.4. Lock all cabinets.

17.0. Water Shutdown

17.1. Turn water control valve from Figure A-1 clockwise (close).

18.0. Network Communication Troubleshooting

If the data on the Lookout HMI screen stops updating frequently (every 3-5 minutes)and seems to lock up, check the Modbus and Serial Port setting on LT11:

18.1. Press Ctrl+Space to go into Edit mode (yellow bar on the bottom of thescreen appears).

18.1.1.

Click Object, then Modify, then expand the ITRCLT11 folder by pressingthe + sign beside it.

18.1.2. Expand the Process1 folder. Choose Modbus1.

18.1.3. Click OK, and the Revise Modbus Secondary will pop up. On the bottom ofthis screen, make sure the Receive timeout: is set as 2000 msecs.

18.1.4. Click OK to finish (leave the COM port as COM6).

18.2. Click Option, then Serial Ports. From the upper-left pull-down menu,choose COM6. Make sure the Receive gap is set as 200 bytes. ClickQuit to finish.

18.3.

Click Ctrl+Space to exit Edit mode and return to Run mode.

19.0. Software Installation

19.1.

Laptop 1 with LabVIEW19.1.1.National Instruments, LabVIEW 7.1 (Disc 1-2, 12, 19-20) or higher

19.1.2.

Industrial Automation OPC Server Ver 5.0

19.1.3.NI-Serial for USB.

19.1.4. Run visa341full.exe, which can be found on the VFD work folder CD.

19.2. Laptop 2 with Lookout

19.2.1.National Instruments, Lookout 5.0 software or higher.

19.2.2. ISaGRAF 3.3 can be installed (v. 3.5 version is single-computer licensesoftware).

19.2.2.1. ISaGRAF is rarely needed; however, it may be used when

troubleshooting or if a PLC code needs to be changed.


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APPENDIX B

Motor Replacement Procedure


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Irrigation Training and Research Center B-1 Electric Motor Efficiencyunder Variable Speeds and Loads

Appendix B: Motor Replacement Procedure

1 Electrical Disconnect

1.1 Turn OFF the Main Disconnect (Panel 1).

1.2

Ensure that the switches on Panels 2 & 3 are both OFF.1.3 Detach Motor Power Cable (Box 5).

1.3.1 Turn dial counterclockwise to the open position.

1.3.2 Turn locking collar clockwise and pull down on plug until it releases. It may benecessary to lift the cap while pulling down on the plug.

1.3.3 Push the cap into position and rotate its locking collar counterclockwise to secureit in place.

1.4 Remove the cover from the electrical access to the motor.

1.5 Disconnect the colored power lines. Set couplers aside for the nextinstallation.

1.6

Disconnect the green ground cable from the motor housing.

1.7 Coil the power cable and set it aside for the next installation.

Figure B-1. Electrical supply for the motor testing

2 Mechanical Disconnect

(Some steps require two persons)

2.1 Remove large nut from top of motor shaft.

From VFD


VFDVFD

Input

VFDOutput

SCADAPack

PLC & Meters

Main

Disconnect

13 4

8 7From

Manual

Across Line

Motor Starter

6

120V

Main

5

To VFD

To

Manual

9

120V

Breaker

Box


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2.2 Remove the chuck and key from the top of the motor.

2.3 Rethread the nut to a position approximately 6 from the top of the motorshaft.

2.4 Let the chuck rest on the top of the nut and reinsert the key. This will serve asa handle to unscrew the motor shaft from the collar that is connecting it to the

pump below.

2.5 Open the access plate above the pump on the pond side of the test stand.

2.6 One person holds the collar with a crescent wrench while the second personturns the shaft clockwise using the chuck.

2.7

Once free, lift the shaft straight up through the motor. Use gloves if necessaryas threads may be sharp.

2.8

Remove the key and chuck from the motor shaft.

2.9 Tape the key to the chuck and replace it on top of the motor.

2.10 Remove collar from pump shaft.

2.11

Return both the collar and the motor shaft to the motor storage area.

3 Motor Removal and Storage

(Requires two persons, one properly trained to operate a lift truck)

3.1 Lift truck operator positions lift truck with one (1) fork centered directlyabove the motor.

3.2 Second person positions sling under the lifting points on each side of themotor and centered over the fork.

3.3 Remove the bolts connecting the motor to the test stand.

3.4

Lift truck operator raises the forks to lift the motor off of the test stand.

3.5 Lift truck operator drives to the shed area and lowers the motor onto itsstorage skid.

3.6

If the adapter plate was used to attach this motor to the test stand, the adapterplate should be removed prior to putting the motor into storage.

3.6.1 Lower the motor with the adapter plate onto a pair of soft wood boards.

3.6.2 Remove the nuts attaching the motor to the adapter plate.

3.6.3 Using the lift truck, lift the motor and place it onto its skid.

3.6.4 If not required for the next installation, return the adapter plate to the storage

area.3.7 Once the motor is securely bolted to its skid, use the lift truck and/or hand

truck to move the motor into the storage area.

4 Motor Installation

(Requires two persons, one properly trained to operate a lift truck)

4.1

Move the next motor to be tested out of the storage area using the hand truck.


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4.2 Remove the bolts holding the motor to its skid.

4.3 Lift truck operator positions lift truck with one (1) fork centered directlyabove the motor.

4.4 Second person positions sling under the lifting points on each side of themotor and centered over the fork.

4.5

Lift truck operator raises the forks to lift the motor off of the skid.

4.6 If the adapter plate is needed to attach this motor to the test stand, it should beattached to the motor at this time.

4.6.1 Place the adapter plate onto a pair of soft wood boards.

4.6.2

The lift truck operator should slowly lower the motor onto the adapter plate,while the second person guides it into position by aligning the bolts on theadapter plate with the mounting holes on the motor.

4.6.3 Firmly tighten the nuts attaching the motor to the adapter plate.

4.6.4 Lift truck operator raises the forks to lift the motor with the adapter plate off ofthe boards.

4.7

Lift truck operator drives to the testing area and raises the motor above the teststand.

4.8 Lift truck operator slowly lowers the motor onto the test stand while thesecond person guides the motor into position by aligning the holes on the teststand with those on the motor (or adapter plate, if used).

4.9 Firmly tighten the nuts and bolts holding the motor to the test stand.

4.10 Lift truck operator can return the lift truck.

5 Mechanical Connection

5.1 Measure the diameter of the hole in the center of the chuck (on the top of themotor) to determine the correct motor shaft diameter.

5.2 Select the shaft with this diameter with its matching nut and collar from thestorage area.

5.3 Thread the collar onto the pump shaft (in the pond-side access panel) until thetop of the pump shaft is aligned with the small hole in the side of the collar.

5.4 Lower the motor shaft through the top of the chuck. Turn the shaftcounterclockwise to thread it onto the collar. Use gloves if necessary, as thethreads may be sharp.

5.5

Align the key slot in the motor shaft with the key slot on the chuck and insertthe key.

5.6 Use a crescent wrench to tight the collar onto the motor shaft using aclockwise rotation.

5.7 Replace the cover on the access panel.

5.8 Thread the large nut onto the motor shaft and tighten it above the chuck.

5.9 Fill the motor with the appropriate weight motor oil.


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5.10 Apply 3-4 squirts of grease to each of three (3) grease fittings.

5.10.1 Upper pump shaft bearings.

5.10.2 Lower pump shaft bearings.

5.10.3

Motor bearing.

6 Electrical Connection

6.1 Verify that the Main Disconnect (Panel 1) is OFF and that the switches onPanels 2 & 3 are both OFF.

6.2 Verify that the power cable you will be installing is in good condition and thatit is disconnected from the power supply.

6.3 Locate the motor wiring plate near the motors electrical access panel.

6.4 If there are multiple wiring schemes, contact Bryan Busch to verify whichshould be followed.

6.5

Remove the cover from the motors electrical access panel. Each wire shouldbe numbered corresponding to the schematic on the wiring plate.

6.6 Complete any internal wiring connections before connecting the externalpower cable.

6.7 Connect the external power cable to the motor.

6.7.1 The green cable is ground and should attach directly to the motor housing.

6.7.2 The red cable is line 1 and will normally connect to line 1 on the motor.

6.7.3 The white cable is line 2 and will normally connect to line 2 on the motor.

6.7.4 The black cable is line 3 and will normally connect to line 3 on the motor.

6.8 Always ensure that the cover is securely over the motors electrical accesspanel before applying power to the motor.

6.9 Connect the power cable to the power supply (Box 5).

6.9.1 Remove the cap from the power supply by turning the locking collarcounterclockwise.

6.9.2 Align the plug of the power cable so that the semi-circle prong is toward the walland lift plug into place.

6.9.3 Turn the locking collar on the plug counterclockwise to secure it.

6.9.4

Turn the dial clockwise to the closed position.

7

VFD Setup7.1 Power up the VFD

7.1.1

Turn Main Disconnect (Panel 1) ON.

7.1.2 Verify that the 120V Main (Panel 6) is ON.

7.1.3 Open Panel 9, 120 V Breaker, and turn on the VFD air conditioner (Unit 7).


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7.1.4 Turn VFD Input (Panel 2) to To VFD. This isthe vertical up position. It takes a few momentsfor the VFD Controller (Unit 8) to come online.

7.1.5 Leave VFD Output (Panel 3) in the OFF position.

7.2 Adjust Motor-Specific Settings

7.2.1

Press Quick Menu button to access settings.

7.2.2 Press + and - buttons to cycle through settings.

7.2.3 Verify each setting with that listed on the motorname plate.

7.2.4 To change a setting press Change Data button.

7.2.4.1 Press the + and - buttons to cycle

through the range of values valid for

that setting.

7.2.4.2 Press OK button when done.

7.2.5 After changing any setting, use the + and -

buttons to cycle through all settings and confirmthey are all correct. (A change in one valuecould affect other values.)

7.3 Prepare VFD for Motor Start Test

7.3.1 Press Hand Start button

7.3.2 Use the + and - buttons to set the speed to 40%.

7.3.3 Press the Off Stop button.

Figure B-3. Motor test stand

Figure B-2. VFD Panel


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8 Motor Start Test

8.1 Confirm that the flow & pressure control valves are closed.

8.1.1 Flow control valve: closed all the way down.

8.1.2 Pressure control valve: closed all the way up.

8.2

Turn VFD Output (Panel 3) to the From VFD (vertical up) position.8.3 Return to the VFD Controller (Unit 8) and press the Hand Start button.

8.4 If the motor is set up correctly and wired properly, you will see the motorshaft spin in the counterclockwise direction. Skip the rest of Section 8.0.

8.5 If the motor shaft spins in the clockwise direction then two of the powercables have been reversed.

8.5.1 Follow Electrical Disconnect steps 1.1. 1.4.

8.5.2 Disconnect and switch any two of the colored power lines (red, white, or black).

8.5.3 Follow Electrical Connection steps 6.8. and VFD Setup steps 7.1.

8.5.4

Return to the beginning of the Motor Start Test 8.08.6 If the motor shaft does not spin, the VFD will automatically shut down the

motor and display a warning message.

8.6.1 Turn VFD Output (Panel 3) to the OFF (horizontal) position.

8.6.2 Contact Bryan Busch to help troubleshoot the problem.

9 Preparing Motor Test Datasheet

9.1 Open the file VFD Pretest.xls

9.2 Open the Tab General and find the motor to be tested based on HP, RPM,

and manufacturer.9.3 Open the Tab corresponding to the motor to be tested.

9.4 You will make changes to the VFD Motor Test Preparation Table (rows 49-84) which will be automatically reflected in the VFD Motor Test Sheet (rows1-45).

9.4.1 Change all of the Load Cell values in column N to 150.

9.4.2 Sort all of the data in cells H50-O84 by the torque values (col M), ranked fromlowest to highest.

9.4.3 Change the Load Cell Location (col O) so that the indicated torque (col M) iswithin the range indicated below.

9.4.3.1

Column M less than 150 ft-lbs, load cell position 1.9.4.3.2 Column M between 150 300 ft-lbs, load cell position 2.

9.4.3.3 Column M between 300 450 ft-lbs, load cell position 3.



9.4.4

Sort all of the data in cells H50-O84, low to high, by the load cell location (colO), the RPM (col I), and the HP (col K).


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9.5 On the VFD Motor Test Sheet (rows 1-45) find the values for Force (col E)and Load Cell Location (col G) for the 100% VFD test.

9.6 Re-type these numbers in the corresponding rows for the Across-the-Line test.

9.7 Before printing, confirm that the Print Area includes only the VFD Motor TestSheet.


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APPENDIX C

Sample Data Sheets


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Irrigation Training and Research Center C-1 Electric Motor Efficiencyunder Variable Speeds and Loads

Appendix C: Example Data Sheets

Sheet 1: Motor Test Data Collection

A01 Warmup start time: Warmup end time: Date:

US Motors, 460V, 24.3A, PF85.6, EFI 87.5, VFD

Stable load

(lb):

Initial shaft

load (lb):

1765 20 Max Amps: People doing test:

Lookout

Laptop 11

computer

time

% Freq.

RPM

Desired

Force

(lbs)

Load Cell

Load

Cell

Location

(ft)

Actual RPMActual Force

(lb)

Shaft Load

(lb)Amperage Low Press. High Press. OK or not? Comment

60% 20 25 1

70% 17 25 1

80% 15 25 1

90% 13 25 1

100% 12 25 1

40% 15 25 2

50% 12 25 2

60% 20 25 2

70% 17 25 2

80% 15 25 280% 22 25 2

90% 13 25 2

90% 20 25 2

90% 20 25 2

100% 12 25 2

100% 12 25 2

100% 18 25 2

40% 20 25 3

50% 16 25 3

60% 20 25 3

70% 17 25 3

70% 23 25 3

80% 20 25 3

80% 20 25 3

90% 18 25 3

100% 16 25 3

40% 22 25 4

50% 18 25 4

50% 24 25 4

60% 20 25 470% 21 25 4

60% 20 25 5

40% 119 150 1

40% 149 150 1

50% 119 150 1

100% 12 25 1

100% 24 25 1

100% 12 25 3

100% 16 25 3

100% 20 25 3Across-the-

line

Max RPM

VFD Motor Test Sheet

Motor Description:

File Name (.csv)

VFD

Norminal HP

Re-entry Loadcell and Loadcell location in Laptop 11 Lookout when do a physical replacement.


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Irrigation Training and Research Center C-2 Electric Motor Efficiencyunder Variable Speeds and Loads

Sheet 2: Calibration Test Sheet

Calibration Test Sheet

Calibrations #1 recorder:

motor:

Lookout weight SCADA weight

1,2,3,4,5 _________ _________ date:

6 _________ _________

7 _________ _________ time:

8 _________ _________

9 _________ _________ air temp:

10 _________ _________

9 _________ _________

8 _________ _________

7 _________ _________

6 _________ _________

5,4,3,2,1 _________ _________

none _________ _________


motor:


1,2,3,4,5 _________ _________ date:

6 _________ _________

7 _________ _________ time:

8 _________ _________

9 _________ _________ air temp:

10 _________ _________

9 _________ _________

8 _________ _________

7 _________ _________6 _________ _________

5,4,3,2,1 _________ _________

none _________ _________


motor:


1,2,3,4,5 _________ _________ date:

6 _________ _________

7 _________ _________ time:

8 _________ _________

9 _________ _________ air temp:

10 _________ _________

9 _________ _________

8 _________ _________

7 _________ _________

6 _________ _________

5,4,3,2,1 _________ _________

none _________ _________


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APPENDIX D

Equipment Descriptions


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Irrigation Training and Research Center D-1 Electric Motor Efficiencyunder Variable Speeds and Loads

Appendix D: Test Equipment Description

Equipment Categories

The test equipment was categorized under the following functions:

1.

Test Motors2. Electrical Supply (electrical current to the motor at the desired frequency)3. Data (electrical and manual inputs/outputs)4. Load Creator (load placed on the motor)5. Torque (created by the motor)

An overall schematic of data (inputs and outputs) collection points and key physicalcomponents is seen in Figure D-1 below.

Figure D-1. Inputs and Outputs

Test Motors

Table D-1 lists the twelve motors tested, along with their nameplate specifications..

VFDAC ATL

Motor

Data

Sheet

Yokogawa

Load

creator

RPM

Monarch

LT21LT11

or

PSI

RPM

Amps

= data

= power

Yokogawa

21 11

Load Cell

Data

Sheet


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Table D-1. Motors used in testing and their nameplate specifications. All were rated at 60 Hz,460 V

ITRC ID Manuf. Nom HPNom.RPM

PF EFI Amps Other

AO1 US 20 1765 85.6 87.5 24.3VFDrated

A02 GE 20 1175 85 91 24.1AO3 US 20 1770 85.4 92.4 23.7 Premium

AO5 US 75 1780 85.3 95 87 Premium

AO6 GE 100 1780 ns 91 124

AO9 US 40 1780 85.7 88.5 49

AO10 GE 75 1785 85 95 87.1

AO11 GE 50 1775 ns ns 61.1

AO12 US 50 1780 87.5 94.5 56 Premium

AO13 US 40 3515 89.5 90.2 46

AO14 US 75 895 74.3 94.1 100

AO15 GE 50 1185 ns 91.7 61.2

Notes: ns = not stated on the nameplate

GE = General ElectricUS = US Motors or Emerson

Electrical SupplyElectricity could be supplied to the test motors either across-the-line (ATL) or throughthe VFD controller. Figure D-2 shows the physical configuration.

Figure D-2. Electrical panel configuration

From VFD


VFDVFD

Input

VFDOutput SCADAPack

PLC & Meters

Main

Disconnect

123 4

8 7From

manual

Across-the-Line

Motor

Starter

6

120V

Main

5

From VFD

From

manual

9

120V

Breaker

Box


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The following are the key elements of the electrical supply:

Danfoss VLT 8000 AQUA (item 8 in Figure D-2) rated for 100 HP.Nameplate information includes:

(815) 639-8600Ref. # : 370858

Ref 2:50T/C: VLT8102AT4CN1STR0DLF00C0IN: 3 x 380 - 480V 50/60 Hz 145A - 128AOUT: 3 x 0 -Vin 0.1 1000 Hz 147A 130A75Kw/100HpSW VER 1.31 005IP20/VL and NEMA TYPE 1TambMax x 40 degrees/ 45 degrees Celsius (104/113 degrees F)Bus option: NONEApplication option: NONESerial #: 000225H144

Code #: 178B5770 Kooltronic RP52 14,000 BTU Air Conditioner connected to the VFD aluminum

enclosure (item 7 in Figure D-2). This air conditioner receives power from a 20amp, double-size breaker

Square D Well-Guard Across-the-Line Starter. Control 100 HP Pump StarterNPJ4100 Class 8940

Square D switch to manually change from the VFD to Across-the-Line to andfrom the alternators. Square D Double Throw Safety Switch 200 Amp/A, 480Vac. Square D 82344RB

Square D Heavy Duty Safety Switch 200 A, 600 Vac, 600 Vdc as a maindisconnect

20A Circuit Breaker. Square D FAL24020 with enclosure FA100RB

Flexible cable for quick connection to the motor. Crouse Hinds quick disconnectconnectors (#CH4125C7W) and quick disconnect plugs (#CH4125P7W) wereused with a 20 Carol Cable #81664

120/240V Sub Panel. Square D 50A Q0612L100RB#2R

10KVA Single Phase Transformer. Square D 10S40F with 50A Backfed main

200A Service Disconnect Switch. Square D H365R


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Data

The following data was measured:

RPM of the motor

Torque developed by the motor, which consisted of:o

The lever arm at which a force was measuredo The force developed

Electric power characteristics before and after the VFD or ATL panel

Motor RPM. The motor RPM was measured with two independent devices. Initially, aMonarch Instruments ACT-2A Panel Tachometer was mounted on the motor test stand,and was used to measure the RPM of the motor shaft.

Figure D-3. Monarch Instruments ACT-2A Panel Tachometer

The Tachometer values were recorded in the Lookout software found in the LT11 laptop,after being registered in a SCADAPack P1 Programmable Logic Controller (PLC).

Figure D-4. SCADAPack P1 PLC

Sometimes the ACT-2A Tachometer RPM values seen on the Lookout screen appeared tobe erratic. Laser/light equipment and reflective tape were used for the readings.

Therefore, readings from a hand-held Extech Instruments Combination PhotoTachometer/Stroboscope (Model 461825) that used reflective tape on the shaft were alsotaken. As long as the two readings were close (within ~5 rpm), the SCADA reading wasrecorded.


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Figure D-5. Extech Instruments Combination Photo Tachometer/Stroboscope

Torque. There are a variety of means to measure torque on a vertical motor. The oneselected for this research utilized a unit that was fabricated by ITRC, following someaspects of a unit used by Weir-Floway for motor testing. The motor was bolted onto a

test stand base plate that could rotate. The vertical motor shaft passed through the standto the load creator (described later). When the motor was energized, it attempted torotate around the shaft, rather than having the shaft rotate inside the motor.

The only thing that prevented the motor from rotating was a long horizontal arm, attachedto the base plate, which exerted a force on an immovable plate some horizontal distancefrom the motor shaft. The base plate assembly was machined to exactly fit variousvertical motor base stands, so that the center alignment was always precise.

There were two critical measurements to determine torque:1. The horizontal distance to the load cell

2.

The horizontal force exerted by the arm at that distance

The original design used a load cell in compression. The load cell could be placed in oneof five locations, depending upon the magnitude of the torque that was to be measured.The locations were precisely surveyed within an accuracy of 0.1 mm, with the distancesshown in Table D-2.

Table D-2. Horizontal load cell distances on pivot arm measured from the center of the verticalmotor.

Average Distances Between Points

Center to 1stCenter to

2nd

Center to

3rd

Center to

4th

Center to

5th

Feet 1.036 2.023 3.013 4.017 5.020

mm 315.7 616.6 918.4 1224.3 1530.0

A pointed attachment was machined to be installed on the end of the load cell, and it wasdesigned to move into a coned depression in the immovable steel frame when the rotatingarm closed the gap. This design proved to be unacceptable for three reasons:


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1. There was a tendency for the load cell to slam into the steel frame when themotor started, thereby destroying the $1500 load cell.

2. The relatively solid fit between the point and the cone transmitted vibrations tothe load cell, thereby destroying other load cells.

3. The fit between a tapered point and cone transmitted vertical forces (due to

vibration and slight un-evenness) to the load cell, giving incorrect results.

Ultimately, a Honeywell Model IC48 150 lb range Load Cell (Order Code AL121CN)was placed in a tension (rather than compression) configuration, which eliminated thethree serious problems described above.

Figure D-6. Honeywell Load Cell

The signal from the Load Cell was run through a Sensotec Model GM Single-ChannelSignal Conditioner/Indicator (Order Code AE213, 56A) enroute to the SCADAPack.

Figure D-7. Sensotec Single-Channel Signal Conditioner/Indicator

The torque was calculated as:

Ft-lb of torque = Distance Force

The output Horsepower of the motor was then computed as:

Output Horsepower = (Ft-lb of torque) (RPM/5,252)

Electric Power. The wave forms of input to a VFD are sinusoidal, while the output waveforms are not. The output wave forms are chopped DC pulses that mimic an AC sinusoid character

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