NREL is a national laboratory of the U.S. Department of Energy, Office of Energy 

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Contract No. DE-AC36-08GO28308

Wind Turbine Generator System 

Acoustic Noise Test Report for 

the ARE 442 Wind Turbine

A. Huskey and J. van Dam

Technical Report

NREL/TP-5000-49179

November 2010
NREL is a national laboratory of the U.S. Department of Energy, Office of Energy 

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, Colorado 80401

303-275-3000 • www.nrel.gov

Contract No. DE-AC36-08GO28308

Wind Turbine Generator 

System Acoustic Noise Test 

Report for the ARE 442 Wind 

Turbine

A. Huskey and J. van Dam

Prepared under Task No(s). WER94501

Technical Report

NREL/TP-5000-49179

November 2010
NOTICE

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Page 1 of 37

Wind Turbine Generator System

Acoustic Noise Test Report

for the 

ARE442 Wind Turbine

Conducted for

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, Colorado 80401

Conducted by

National Wind Technology Center

National Renewable Energy Laboratory

1617 Cole Boulevard

Golden, Colorado 80401

Arlinda Huskey, Jeroen van Dam

August 3, 2010
Page 2 of 37

Notice

This report was prepared by the National Renewable Energy Laboratory (NREL), operated for the United 

States Department of Energy (DOE) by the Alliance for Sustainable Energy, LLC (Alliance), as an 

account of work sponsored by the United States government. The test results documented in this report 

define the characteristics of the test article as configured and under the conditions tested.

THIS REPORT IS PROVIDED "AS IS" AND NEITHER THE GOVERNMENT, ALLIANCE, 

NREL NOR ANY OF THEIR EMPLOYEES, MAKES ANY WARRANTY, EXPRESS OR 

IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS 

FOR A PARTICULAR PURPOSE, OR ASSUMES ANY LEGAL LIABILITY OR 

RESPONSIBILITY FOR THE ACCURACY, COMPLETENESS, OR USEFULNESS OF ANY 

SUCH INFORMATION DISCLOSED IN THE REPORT, OR OF ANY APPARATUS, 

PRODUCT, OR PROCESS DISCLOSED, OR REPRESENTS THAT ITS USE WOULD NOT 

INFRINGE PRIVATELY OWNED RIGHTS. 

Neither Alliance nor the U. S. Government shall be liable for special, consequential or incidental 

damages. Reference herein to any specific commercial product, process, or service by trade name, 

trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, 

recommendation, or favoring by the United States government or any agency thereof. The views and 

opinions of the authors expressed herein do not necessarily state or reflect those of the United States 

government or any agency thereof or Alliance. 

NREL is a DOE Laboratory, and as an adjunct of the United States government, cannot certify wind 

turbines. The information in this report is limited to NREL’s knowledge and understanding as of this date. 

NREL is accredited by the American Association for Laboratory Accreditation (A2LA) and the results 

shown in this test report have been determined in accordance with the NREL’s terms of accreditation 

unless stated otherwise in the report.

This report shall not be reproduced, except in full, without the written approval of Alliance or successor 

operator of NREL.

Approval By: _________________________________________________________________

Jeroen van Dam, NREL Test Engineer Date

Review By: __________________________________________________________________

Sarah Taubitz, NREL Test Engineer Date
Page 3 of 37

Table of Contents

2. LIST OF TABLES............................................................................................................................... 4

3. LIST OF FIGURES............................................................................................................................. 4

4. BACKGROUND.................................................................................................................................. 5

5. TEST TURBINE CONFIGURATION .............................................................................................. 5

6. TEST SITE........................................................................................................................................... 7

7. DESCRIPTION OF TEST EQUIPMENT ........................................................................................ 9

8. RESULTS........................................................................................................................................... 10

9. UNCERTAINTY................................................................................................................................ 19

10. EXCEPTIONS................................................................................................................................ 20

11. REFERENCES............................................................................................................................... 20

APPENDIX A: PICTURES OF TEST SITE.......................................................................................... 21

APPENDIX B: CALIBRATION SHEETS FOR INSTRUMENTS ..................................................... 23
Page 4 of 37

List of Tables

Table 1. Test turbine configuration............................................................................................................... 5

Table 2. Rotor speed at integer standardized wind speeds............................................................................ 7

Table 3. Nearby noise sources...................................................................................................................... 8

Table 4. Equipment list................................................................................................................................. 9

Table 5. Sound power levels for integer wind speeds 4 m/s through 12 m/s.............................................. 13

Table 6. Background corrected Third octave spectra for several wind speeds........................................... 16

Table 7. Tonality results ............................................................................................................................. 17

Table 8. Type B Uncertainty Components for Apparent Sound Power Level............................................ 19

Table 9. Type B Uncertainty Components for third octave spectra............................................................ 19

Table 10. Type B Uncertainty Components for Tonality ........................................................................... 20

List of Figures

Figure 1. One line diagram of the ARE 442 installation............................................................................... 6

Figure 2. ARE 442 test turbine at the NWTC. PIX ..................................................................................... 7

Figure 3. Map of the test site ........................................................................................................................ 8

Figure 4. Location of the data acquisition sensors...................................................................................... 10

Figure 5. Standardized wind speed during the measurement period........................................................... 11

Figure 6. Wind direction during the measurement period .......................................................................... 11

Figure 7. Measure air temperature and air pressure during the measurement period ................................. 12

Figure 8. Measured 10 second averaged sound pressure levels as a function of standardized wind speed 13

Figure 9. Apparent sound power level as a function of standardized wind speed. ..................................... 14

Figure 10. Third octave spectra for several integer wind speeds................................................................ 15

Figure 11. Example of critical band and classification of lines for 8 m/s................................................... 17

Figure 12. Example of critical band and classification of lines for 9 m/s................................................... 18

Figure 13. Example of critical band and classification of lines for 10 m/s................................................. 18
Page 5 of 37

Background

This test was conducted as part of the U.S. Department of Energy’s (DOE's) Independent Testing project. 

This project was established to help reduce the barriers of wind energy expansion by providing 

independent testing results for small turbines. In total, five turbines are being tested at the National Wind 

Technology Center (NWTC) as a part of this project. Acoustic noise testing is one of up to five tests that 

may be performed on the turbines, including duration, safety and function, power performance, and 

power quality tests. 

The acoustic noise test was conducted to the IEC 61400-11 Edition 2.1.

Test Turbine Configuration

The test turbine (Figure 2) is a variable speed, free yawing, three-bladed, upwind, furling turbine with a 

rated power of 10kW. Table 1 lists the basic turbine configuration and operational data. Both sides of 

each blade tip had trip strips bonded to them. However, it was found that the trip strips on the high 

pressure sides of all three blades had come off when the turbine was uninstalled in December 2009.

Figure 2 shows the electrical diagram for the test turbine installation. Table 2 gives the rotor speed at 

integer wind speeds.

Table 1. Test turbine configuration

Manufacturer Abundant Renewable Energy

Model number ARE 442

Serial number Y08-001C

Vertical or horizontal axis Horizontal axis

Upwind or downwind rotor Up wind

Rotor center height 30.9 m

Horizontal distance from rotor center to tower 

axis

0.82 m

Diameter of rotor 7.2 m

Stall or pitch-controlled turbine Stall, with furling

Fixed or variable pitch Fixed

Rotational speed at reference wind speed (8 m/s) 120 rpm

Rotational speed at rated power 140 rpm

Pitch angle 0° blade root flat on alternator surface

Rated power output 10 kW

Tower type (lattice or tube) Lattice

Tower height 30.5 m

Rotor control devices Furling, dynamic brake

Blade type Aero Energy

Number of blades 3

Drivetrain Direct drive

Constant/variable speed Variable speed

Control software version Not available

Generator details Permanent magnet
Page 6 of 37

Tower base 

J-box

Uptower 

J-box

Foundation 

junction box

Met tower 

j-box

Voltage 

clamp

Resistive 

dump 

load

Resistive 

dump 

load

inverterinverter

Sub panel

Power 

measure

ment box

60A 600V 

disconne

ct

kWh 

meter

Power panel 3-3L 

120/240V

2*10AWG

L1

datashed

3*6AWG

4*14AWG

AWG 4* 3

AWG 14 * 4

LP 14106 

surge 

suppressor

) AWG 4( Ground 

Ground (6AWG)

LP 14106 

surge 

suppressor

Ground rod on the 

southeast corner

G

L1

L1L2

G

Ground rod on the north 

side of datashed

ZD16100 

surge 

suppressor

L2

2 pole 30A 

breaker 3*10AWG

3*10AWG

1*10AWG

2*14AWG

2*10AWG

1*10AWG

2*14AWG

2 pole 30A 

breaker

1 pole 15A 

breaker

2 pole 60A 

breaker 

no.27-29

Everything between subpanel and panel 

3-3 L 6AWG

L

N

2

8AWG

8AWG

NREL 

grid 2*12AWG

2 pole 30A 

breaker

60A 600V 

disconnect

Shorting switch

SOW

Figure 1. Electrical diagram of the ARE 442 installation
Page 7 of 37

Figure 2. ARE 442 test turbine at the NWTC. PIX #17819

Table 2. Rotor speed at integer standardized wind speeds

Wind speed [m/s] 6 7 8 9 10

Rotor speed [rpm] 107 114 121 130 137

Test Site

The test turbine is located at site 3.3a at the National Wind Technology Center, located 8 miles south of 

Boulder, Colorado, in mostly flat terrain with short vegetation; the roughness length is estimated as 

0.05m. The test site has prevailing winds bearing 292 degrees relative to true north. For measurements 

where it is important to accurately measure wind speed, NREL used data obtained when wind direction 

was between 214° and 74° degrees true. In this measurement sector, established in accordance with IEC 

61400-12-1, the influence of terrain and obstructions on the anemometer and turbine are small. Figure 4

shows the turbine and meteorological tower locations. This figure also shows nearby obstructions and 

topographical features of the site. A circle indicating 20 rotor diameters is drawn in the map.

Table 3 provides the neighboring turbines and their operating status during the noise test. The Controls 

Advanced Research Turbine CART was running through part of the measurements. Measurements taken 

when the CART was running were not used for third octave or tonality analysis. They were used for 
Page 8 of 37

determination of sound power level, after it was verified that the CART did not have an effect and that 

data blended in with the other data sets. 

Pictures of the sound board location, test turbine, and met tower can be found in Appendix A. No picture 

was taken of the microphone on the soundboard. 

Table 3. Nearby noise sources

Source Location Shutdown 

during noise test

NW100b 3.4 Yes

Gaia 11kW 3.3b Yes

Southwest Windpower Skystream (2*) 3.2 Yes

Endurance 3.1 Yes

CART 4.2 No and Yes

Bergey Excel 1.4 No

Figure 3. Map of the test site

N
Page 9 of 37

Description of test equipment

All test equipment was calibrated; calibration sheets are included in Appendix B. Table 4 shows the 

equipment used and calibration due dates. The anemometer was located at 31.2m height.

The data acquisition modules were out of calibration during the test period. They were sent out for posttest calibration and found to be within specification. Thus, no additional uncertainly was added to the 

results. The post-test calibration sheets are included in Appendix B as well.

Table 4 shows the list of instrumentation that was used for the test. Figure 4 shows the location of the 

instrumentation on the meteorological tower. The meteorological tower was located 2.5 rotor diameters 

upwind of the turbine in the predominant wind direction.

Table 4. Equipment list

Instrument Make, Model Serial Number Calibration Due Date

Power transducer Secondwind Phaser 5FM-4A20 02663 28 Apr 2009

Current transducers OSI 12974 001235408

001235411

Calibrated with power 

transducer 

Primary anemometer Thies, First Class 0707888 2 Feb 2010

Reference anemometer NRG, Max 40 179500049022 In situ

Wind vane Met One, 020C with aluminum vane G4706 28 Feb 2009

Pressure sensor Vaisala, PTB101B T4730007 26 Aug 2009

Temperature sensor Met One, T-200 0789020 10 Oct 2009

Data acquisition system Compact DAQ w/LabView-based data 

acquisition

cDAQ-9172

NI 9229

NI 9217

NI 9205

12EAE14

12A2037

12C73B4

12ECB77

31 May 2008

3 Aug 2008

9 Oct 2008

Digital Recorder and 

Signal Analyzer

Delta Acoustics NoiseLab 1258E43 24 Nov 2010

Microphone Bruel & Kjaer, 4189-A-021 2395206 21 Nov 2010

Preamplifier Bruel & Kjaer, 4012 2373719 21 Nov 2010

Calibrator Bruel & Kjaer, 4230 2326144 11 Nov 2009
Page 10 of 37

Figure 4. Location of the data acquisition sensors

Results

Turbine and background data was collected on 26 February 2009, 11:20 - 16:50. Winds were coming out 

of the WNW direction. The sound board location was directly downwind of the turbine for winds out of 

the 291 direction at a distance of 34.5 m. Data was used only if the wind direction was within 15 degrees 

of the 291 direction.

Wind speed was measured and not derived from power. NREL research has shown that this method gives

a better correlation with noise data for small wind turbines.

Plots of wind speed, wind direction, air temperature, and air pressure during the measurement period are 

given in Figure 5 through 7.

A total of 346 ten second data points of turbine data and 156 ten second data points of background data 

were used in the analysis.
Page 11 of 37

0

5

10

15

20

25

11:16 12:28 13:40 14:52 16:04 17:16

Vs, standardized wind speed [m/s]

Time

Figure 5. Standardized wind speed during the measurement period

0

50

100

150

200

250

300

350

400

11:16 12:28 13:40 14:52 16:04 17:16

Wind direction [°]

Time

Figure 6. Wind direction during the measurement period
Page 12 of 37

80

80.1

80.2

80.3

80.4

80.5

80.6

80.7

80.8

80.9

81

0

2

4

6

8

10

12

14

16

18

20

11:16 12:28 13:40 14:52 16:04 17:16

Air pressure [kPa]

Air temperature [°C]

Time

Air temperature

Air pressure

Figure 7. Measure air temperature and air pressure during the measurement period

Figure 8 shows the measured data pairs. The method of bins was used to calculate the bin average turbine 

and background sound pressure level. The sound pressure levels at the integer wind speeds were 

interpolated between bins. The background correction was then applied to the bin averaged values at the 

integer wind speeds. Figure 9 and Table 5 give the calculated apparent sound power levels, with the 

combined uncertainty for each integer wind speed.
Page 13 of 37

Figure 8. Measured 10 second averaged sound pressure levels as a function of standardized wind 

speed

Table 5. Sound power levels for integer wind speeds 4 m/s through 12 m/s

Wind Speed 

Bin

Sound Power 

Level

Combined 

Uncertainty

Type A 

uncertainty

Type B 

uncertainty

[m/s] [dB (A)] [dB (A)] [dB(A)] [dB(A)]

4 85.8 2.6 2.5 0.8

5 85.9 1.7 1.5 0.8

6 85.2 1.7 1.5 0.9

7 84.9* 2.0 1.3 1.6

8 87.6 2.3 1.8 1.4

9 89.9 2.3 1.2 1.9

10 93.7 2.9 2.2 1.9

11 96.5 2.3 1.7 1.6

12 98.2 1.3 1.0 0.8

* Background noise was within 3-6 dB(A) of overall noise
Page 14 of 37

60

65

70

75

80

85

90

95

100

105

110

0 2 4 6 8 10 12 14

LWA, Apparent Sound Power Level [dB(A)]

Vs, Standardised wind speed [m/s]

Figure 9. Apparent sound power level as a function of standardized wind speed.
Page 15 of 37

The A-weighted third octave spectra were calculated for each bin. Table 6 and Figure 10 give the results. 

For several wind speeds, at the high and low frequencies, the separation between turbine and background 

was insufficient to report a value. Only spectra for bins, in which at least 10 data points were recorded for 

both turbine and background, are reported. For bands that have no value listed, the background noise was 

within 3dB(A) of the overall noise.

0

10

20

30

40

50

60

Sound pressure level [dB(A)]

Frequency [Hz]

5 m/s

6 m/s

7 m/s

8 m/s

9 m/s

10 m/s

Figure 10. Third octave spectra for several integer wind speeds.
Page 16 of 37

Table 6. Background corrected Third octave spectra for several wind speeds

5 [m/s] 6 [m/s] 7 [m/s] 8 [m/s] 9 [m/s] 10 [m/s]

Freq

[Hz]

Ls 

[dB(A)]

UC 

[dB(A)]

Ls 

[dB(A)]

UC 

[dB(A)]

Ls 

[dB(A)]

UC 

[dB(A)]

Ls 

[dB(A)]

UC 

[dB(A)]

Ls 

[dB(A)]

UC 

[dB(A)]

Ls 

[dB(A)]

UC 

[dB(A)]

50

63

80

100

125

160 36.6 2.3

200 35* 4.1 41.2 3.2 45.7 2.1 46.8 2.1 44.8 1.9

250 41.1 3.4 46.5 4.6 55.1 2.3

315 36.7 2.2 34.8* 2.7 36.6* 2.5 38.7* 2.4

400 33.3 2.4 33* 2.4 35* 2.3 36* 2.3 37.3* 2.3 38.3* 2.3

500 34.9 2.0 34.8 2.1 34.1* 2.3 35.3* 2.5 37.2* 2.8 41.1 2.2

630 38.2 2.0 38.3 2.5 36.5 2.3 38.0 2.2 39.3 2.2 40.7 2.2

800 38.7 1.9 37.4 2.1 35.9* 2.3 37.4 2.2 39.0 2.3 41.5 2.1

1000 39.4 1.9 38.5 2.1 37.1 2.1 38.2 2.2 39.6 2.3 41.7 2.0

1250 38.5 1.9 38.2 2.0 36.9 2.1 38.4 2.1 39.9 2.1 41.5 2.0

1600 36.3 1.9 36.3 2.0 35.1 2.1 36.7 2.1 38.0 2.2 39.8 2.1

2000 33.5 1.9 34.0 1.9 33.5 2.1 34.9 2.1 36.0 2.2 37.6 2.1

2500 29.9 2.1 31.8 2.0 33.0 2.1 34.7 1.9 35.6 2.0 37.1 2.0

3150 27.2 2.2 28.7 2.1 30.2 2.8 34.4 2.1 36.3 2.2 38.8 2.0

4000 23.5 2.3 24.5* 2.2 25.7* 2.8 29.6 2.2 31.4 2.8 35.8 2.2

5000 25.6* 2.4 27* 2.7 30.4 2.3

6300 26.7* 2.4

8000

10000

* Background noise was within 3-6 dB(A) of overall noise

The tonality analysis resulted in one reportable tone for 8, 9, and 10 m/s. The tonality analysis results,

including the standard uncertainties, are given in Table 7. Figure 11, Figure 12, and Figure 13 show an

example of a 10 second spectrum, with line classification for 8, 9, and 10 m/s.
Page 17 of 37

Table 7. Tonality results

k (m/s): 8 9 10

Freq [Hz]: 240 240 243

∆Ltn1,k -13.6 7.3 5.1

∆Ltn2,k -13.6 -13.6 -13.6

∆Ltn3,k -13.6 -13.6 5.9

∆Ltn4,k -13.6 -13.6 4.2

∆Ltn5,k -13.6 -13.6 -13.6

∆Ltn6,k -13.6 -13.6 8.3

∆Ltn7,k -13.6 -13.6 -13.6

∆Ltn8,k -13.6 -13.6 9.8

∆Ltn9,k -13.6 11.1 -13.6

∆Ltn10,k 8.7 -13.6 -13.6

∆Ltn11,k 9.4 -13.6 -13.6

∆Ltn12,k -13.6 4.9 10.7

∆Lk dB(A) 1.4 2.6 5.0

∆La,k dB(A) 3.5 4.6 7.1

UA dB(A) 6.7 10.6 4.4

UB dB(A) 2.2 2.1 2.0

UC dB(A) 7.1 10.8 4.9

20

25

30

35

40

45

50

189 195 201 207 213 219 225 231 237 243 249 255 261 267 273 279 285 291

Sound pressure level [dB(A)]

Frequency [Hz]

Masking

Tone

Figure 11. Example of critical band and classification of lines for 8 m/s
Page 18 of 37

20

25

30

35

40

45

50

55

189 195 201 207 213 219 225 231 237 243 249 255 261 267 273 279 285 291

Sound Pressure level [dB(A)]

Frequency [Hz]

Masking

Neither

Tone

Figure 12. Example of critical band and classification of lines for 9 m/s

20

25

30

35

40

45

50

192 198 204 210 216 222 228 234 240 246 252 258 264 270 276 282 288 294

Sound pressure level [dB(A)]

Frequency [Hz]

Masking

Tone

Figure 13. Example of critical band and classification of lines for 10 m/s
Page 19 of 37

Uncertainty

The Type A uncertainty for the apparent sound pressure level is the standard error of the estimated LAeq

and is calculated per the Annex D of the standard for each bin. For the Type B uncertainty, the typical 

values from the standard are used except for UB7 and UB9.

For UB7, an uncertainty of 0.5 m/s is assumed. This value is multiplied by the wind speed dependence 

(dB(A)/(m/s)) of the sound power level in each bin.

For UB9, the actual background correction in each wind speed bin is used.

Table 8. Type B Uncertainty Components for Apparent Sound Power Level

Componen Description Value Uni Source

UB1 Calibration 0.2 dB Estimate

UB2 Instrument 0.2 dB Estimate

UB3 Board 0.3 dB Estimate

UB4 Distance 0.1 dB Estimate

UB5 Impedance 0.1 dB Estimate

UB6 Turbulence 0.4 dB Estimate

UB7 Measured wind Bin dB Assume 0.5 m/s uncertainty

UB8 Direction 0.3 dB Estimate

UB9 Background Bin dB Applied background 

For the uncertainty on the third octave bands, the typical values from the standards were used except for 

UB7 and UB9. For UB7 a wind speed uncertainty of 0.5m/s was used in combination with the wind speed 

dependence of the band level. For UB9, the actual background correction in the band was used. Table 9

lists the values used.

Table 9. Type B Uncertainty Components for third octave spectra

Componen Description Value Uni Source

UB1 Calibration 0.2 dB Estimate

UB2 Instrument 0.2 dB Estimate

UB3 Board 1.7 dB Estimate

UB4 Distance 0.1 dB Estimate

UB5 Impedance 0.1 dB Estimate

UB6 Turbulence 0.4 dB Estimate

UB7 Measured wind Bin dB Assume 0.5 m/s uncertainty

UB8 Direction 0.3 dB Estimate

UB9 Background Bin dB Applied background 

For tonality, for the Type B uncertainty, the recommendations from the standard were used. Table 10

shows the values used.
Page 20 of 37

Table 10. Type B Uncertainty Components for Tonality

Componen Description Value Uni Source

UB1 Calibration 0.1 dB Estimate

UB2 Instrument 0.2 dB Estimate

UB3 Board 1.7 dB Estimate

UB4 Distance 0.05 dB Estimate

UB5 Impedance 0.1 dB Estimate

UB6 Turbulence 0.2 dB Estimate

UB7 Measured wind 0.9 dB Assume 0.5 m/s uncertainty

UB8 Direction 0.3 dB Estimate

UB9 Background Bin 

dependent

dB Average of difference of Lpn,ave and background level at 

tone frequency

UB9 at 8m/s: 0.88, 9m/s: 0.77, and 10m/s: 0.5dB

Exceptions

The control software version was not available. A table with measured rotor speeds is provided in Table 

2. The turbine did not use pitch control.

Exceptions to Standard

The averaging period used was ten seconds, instead of one minute. Research by NREL has shown this 

provides a better correlation of sound with wind speed.

The sound power level at 7 m/s was reported even though the background noise was within 3-6dB of total 

noise. If anything, the reported value is conservatively high.

No picture is available of the microphone and wind screen on the soundboard.

DAS modules were out of calibration. The modules were post-test calibrated and found within 

specification. Thus, additional uncertainty was not necessary.

Exceptions to NWTC Quality Assurance System

There were no exceptions to the test plan.

Deviations from the Test Plan

References

IEC 61400-11 Ed 2.1 2006-11 Wind Turbine Generator Systems – Part 11 Acoustic Noise Measurement 

Techniques
Page 21 of 37

Appendix A: Pictures of Test Site

Figure A.1. Picture taken from microphone position towards the turbine. PIX #17919
Page 22 of 37

Figure A.2. Picture taken from the meteorological tower (in the foreground) toward the turbine.

PIX #17816

Figure A.3. Close up of soundboard and surroundings without microphone. PIX #17817
Page 23 of 37

Appendix B: Calibration Sheets for Instruments
Page 24 of 37

Figure B.1. NoiseLAB calibration sheet
Page 25 of 37

Figure B.2. Acoustical Calibrator calibration sheet
Page 26 of 37

Figure B.3. Microphone and preamplifier calibration sheet
Page 27 of 37

Figure B.4. Power transducer calibration sheet
Page 28 of 37

Figure B.5. Anemometer calibration report
Page 29 of 37

Figure B.6. Wind vane calibration report
Page 30 of 37

Figure B.7. RTD calibration report
Page 31 of 37

Figure B.8. Pressure transmitter calibration sheet
Page 32 of 37

Figure B.9. NI 9217 data acquisition module calibration sheet I
Page 33 of 37

Figure B.10. NI 9229 data acquisition module calibration sheet I
Page 34 of 37

Figure B.11. NI 9205 data acquisition module calibration sheet I
Page 35 of 37

Figure B.12. NI 9229 data acquisition module calibration sheet II
Page 36 of 37

Figure B.13. NI 9217 data acquisition module calibration sheet II
Page 37 of 37

Figure B.14. NI 9205 data acquisition module calibration sheet II
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1. REPORT DATE (DD-MM-YYYY)

November 2010

2. REPORT TYPE

Technical Report

3. DATES COVERED (From - To)

4. TITLE AND SUBTITLE

Wind Turbine Generator System Acoustic Noise Test Report for the 

ARE442 Wind Turbine

5a. CONTRACT NUMBER

DE-AC36-08GO28308

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

A. Huskey and J. van Dam

5d. PROJECT NUMBER

NREL/TP-5000-49179

5e. TASK NUMBER

WER9 4501

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Renewable Energy Laboratory

1617 Cole Blvd.

Golden, CO 80401-3393

8. PERFORMING ORGANIZATION

REPORT NUMBER

NREL/TP-5000-49179

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)

NREL

11. SPONSORING/MONITORING

AGENCY REPORT NUMBER

12. DISTRIBUTION AVAILABILITY STATEMENT

National Technical Information Service

U.S. Department of Commerce

5285 Port Royal Road

Springfield, VA 22161

13. SUPPLEMENTARY NOTES

14. ABSTRACT (Maximum 200 Words)

This test was conducted on the ARE 442 as part of the U.S. Department of Energy’s (DOE's) Independent Testing 

project. This project was established to help reduce the barriers of wind energy expansion by providing independent 

testing results for small turbines. In total, five turbines are being tested at the National Wind Technology Center 

(NWTC) as a part of this project. Acoustic noise testing is one of up to five tests that may be performed on the 

turbines, including duration, safety and function, power performance, and power quality tests. The acoustic noise test 

was conducted to the IEC 61400-11 Edition 2.1. 

15. SUBJECT TERMS

Independent Testing project; small wind turbine; ARE 442; acoustic noise testing

16. SECURITY CLASSIFICATION OF: 17. LIMITATION 

OF ABSTRACT

UL

18. NUMBER 

OF PAGES

19a. NAME OF RESPONSIBLE PERSON

a. REPORT

Unclassified

b. ABSTRACT

Unclassified

c. THIS PAGE

Unclassified 19b. TELEPHONE NUMBER (Include area code)

Standard Form 298 (Rev. 8/98)

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