Technical Report

NREL/TP-500-47030

February 2010

Wind Turbine Safety and 

Function Test Report for the 

ARE 442 Wind Turbine

J. van Dam, D. Baker, and D. Jager
National Renewable Energy Laboratory

1617 Cole Boulevard, Golden, Colorado 80401-3393

303-275-3000 • www.nrel.gov

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

Office of Energy Efficiency and Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC

Contract No. DE-AC36-08-GO28308

Technical Report

NREL/TP-xxx-xxxxx

Month Year (Arial 12 pt Bold)

Wind Turbine Safety and 

Function Test Report for the 

ARE 442 Wind Turbine

J. van Dam, D. Baker, and D. Jager

Prepared under Task No. WE10.2211
NOTICE

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

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iii

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 

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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

Approval By: _________________________________________________________________

Amy Bowen, NREL Test Engineer Date
iv

Table of Contents

Background............................................................................................................................... 1

Test Objective........................................................................................................................... 1

Description of Test Turbine and Setup.................................................................................. 1

Instrumentation........................................................................................................................ 5

Procedure.................................................................................................................................. 6

Control and Protection System Functions.............................................................................. 6

Personnel Safety Provisions .................................................................................................... 7

Dynamic Behavior.................................................................................................................... 7

Results....................................................................................................................................... 7

Control and Protection System Functions.............................................................................. 7

Power control...................................................................................................................... 8

Rotor speed control............................................................................................................. 8

Yaw orientation .................................................................................................................. 8

Startup................................................................................................................................. 8

Normal Shutdown............................................................................................................... 8

Emergency shutdown during operation from any operating condition .............................. 8

Behavior upon excessive vibration..................................................................................... 9

Behavior upon loss of load ................................................................................................. 9

Turbine specific checks............................................................................................................ 9

Over temperature ................................................................................................................ 9

Load brake resistor failure simulation ................................................................................ 9

Personnel Safety Provisions .................................................................................................. 10

Safety Instructions................................................................................................................ 10

Climbing ............................................................................................................................... 10

Fire resistance and control .................................................................................................. 11

Fire extinguisher .................................................................................................................. 11

Emergency Stop Button ........................................................................................................ 11

Lock-out / tag-out provisions................................................................................................ 11

Interlock on electrical cabinets............................................................................................ 11

Safety signs....................................................................................................................... 11

Unauthorized changing of control settings.......................................................................... 11

Lighting Protection............................................................................................................... 12

Presence of rotor and yaw lock ............................................................................................ 12

Dynamic Behavior................................................................................................................ 12

Deviations and Exceptions..................................................................................................... 20

Deviations from the Standard............................................................................................... 20

Exceptions to the NWTC Quality Assurance System............................................................ 20

Appendix A – Instrument Calibration Sheets..................................................................... 21
v

List of Figures

Figure 1. ARE 442 wind turbine at the NWTC test site ............................................................ 3

Figure 2. Electrical Drawing of the ARE 442 installation......................................................... 4

Figure 3. Power response to wind speed (red- maxima, green - minima, blue -average)........ 12

Figure 4. Rotor speed response to wind speed (red- maxima, green - minima, blue -average)13

Figure 5. Time series of a high rpm event (datafile ARE081230_001156)............................. 14

Figure 6. Turbine response during a simulated grid outage -- the IGBT’s failed. (datafile 

ARE081105_144425)........................................................................................................ 15

Figure 7. Simulated grid outage in low winds (data file ARE090720_115146)...................... 16

Figure 8. ARE442 Voltage clamp with e-stop button.............................................................. 17

Figure 9. ARE 442 disconnect ................................................................................................. 18

Figure 10. Safety instructions on the voltage clamp................................................................ 19

Figure 11. Safety instruction tag on the TUF TUG climbing system...................................... 20

Figure A.1. Power transducer calibration sheet ....................................................................... 21

Figure A.2. Primary anemometer calibration sheet ................................................................. 22

Figure A.4. NI 9229 data acquisition module calibration sheet I ............................................ 23

Figure A.5. NI 9217 data acquisition module calibration sheet I ............................................ 24

Figure A.6. NI 9205 data acquisition module calibration sheet I ............................................ 25

Figure A.7. NI 9229 data acquisition module calibration sheet II........................................... 26

Figure A.8. NI 9217 data acquisition module calibration sheet II........................................... 27

Figure A.9. NI 9205 data acquisition module calibration sheet II........................................... 28

List of Tables

Table 1. Test Turbine Configuration.......................................................................................... 2

Table 2. Equipment List for Safety and Function Test.............................................................. 5
1

Background

This test was conducted as part of the U.S. Department of Energy’s (DOE) 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, four turbines 

were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety 

and function testing is one of up to five tests that were performed on the turbines, including 

power performance, duration, noise, and power quality tests. Test results provide 

manufacturers with reports that can be used for small wind turbine certification.

The test equipment includes an ARE 442 wind turbine mounted on a 100-ft free-standing 

lattice tower. The system was installed by the NWTC Site Operations group with guidance 

and assistance from Abundant Renewable Energy. 

Test Objective

The objective of this test is to: 

• verify that the test turbine displays the behavior predicted in the design

• determine if provisions relating to personnel safety are properly implemented

• characterize the dynamic behavior of the wind turbine at rated wind speed and above.

NREL does not limit the safety and function test to features described in the wind turbine 

documentation. NREL also inspects, possibly tests, and reports on features that are required 

by IEC 61400-2 that may not be described in the wind turbine documentation. 

NREL conducted this test in accordance with Section 9.6 of the International Electrotechnical 

Commission (IEC) standard, Wind Turbines – Part 2: Design requirements for small wind 

turbines, IEC 61400-2, Second edition, 2006-03.

Description of Test Turbine and Setup

The test turbine was an ARE 442 wind turbine. This turbine is an upwind three-bladed side 

furling turbine with a rated power of 10kW. Table 1 provides the key descriptive information 

of the test turbine.

The ARE 442 wind turbine was installed at site 3.3a at the National Wind Technology Center 

located eight miles south of Boulder, Colorado (Figure 1). The location primarily consists of 

mostly flat terrain with short vegetation. The test site has prevailing wind, bearing 292 

degrees, relative to true north (292°T). For measurements where it is important to accurately 

measure wind speed, NREL used data obtained when wind direction is between 214°T and

72°T. In this measurement sector, which was established in accordance with IEC 61400-12-1, 

the influence of terrain and obstructions on the anemometer and turbine is small.

A one line diagram of the turbine system is provided in Figure 2.
2

Table 1. Test Turbine Configuration

Turbine manufacturer and address Abundant Renewable Energy

22700 NE Mountain Top Road

Newberg OR 97132

Model name ARE 442

Serial number Y08-001C

Production date January 2008

Design nominal voltage at terminals 

(VAC)

240

Maximum current at terminals (A) 55

Design frequency at terminals (Hz) 60

SWT class II

Design 50-year extreme wind speed, 

Ve50

59.5

(m/s)

Rotor Diameter (m) 7.2

Hub Height (vertical center of rotor) 

(m)

30.9

Tower Type Freestanding Lattice Valmont U4.5 x 100’

Rated Electrical Power (kW) 10

Rated Wind Speed (m/s) (lowest 

wind speed at which turbine 

produces rated power)

11

Rated rotor speed (rpm) (lowest 

rotor speed at which turbine 

produces rated power)

140

Rotor speed range (rpm) 0-160

Fixed or variable pitch Fixed

Number of Blades 3

Blade Tip Pitch Angle (deg) 0, blade root flat on alternator

Blade make, type, serial number Aero Energy 089-028, 089-029, 089-030

Description of control system 

(device & software version)

Combination of side furling with gravity return, 

VCL 442-HV voltage clamp and Windyboy 

US6000 inverter software.
3

Figure 1. ARE 442 wind turbine at the NWTC test site
4

Figure 2. Electrical Drawing of the ARE 442 installation
5

Instrumentation

The following parameters were measured in this test: wind speed, electrical power, rotor 

speed, and grid voltage. NREL calculated the rotor speed by measuring the frequency of the 

wild AC (variable voltage, variable frequency) coming from the alternator.

An indication of turbine status was obtained by measuring the status of the relays that activate 

the brake resistors up in the yaw head. The signal is zero when the generator is shorted, and 

five when it is not.

The instruments that were used for these measurements are listed in Table 2. The calibration 

sheets for the instruments used for this safety and function test are included in Appendix A.

Table 2. Equipment List for Safety and Function Test

Instrument Make, Model Serial 

Number

Calibration Due 

Date

Power transducer Secondwind Phaser 5FM4A2002663 April 28, 2009

Current transducers OSI 12974 001235408

001235411

Calibrated with 

Power transducer, 

April 28, 2009

Primary anemometer Thies, First Class 0707886 Feb. 28, 2009

Reference 

anemometer

NRG, Max 40 179500049022 In situ

Rotor speed OSI Voltage Transducer VT7-

010E-11

08010700 April 28, 2009

Data acquisition 

system

Compact DAQ w/LabView 

based data acquisition

cDAQ-9172

NI 9229

NI 9217

NI 9205

12EAE14

12A2037

12C73B4

12ECB77

May 31, 2008

Aug. 3, 2008

Oct. 9, 2008 

Modules calibrated

post-test on May

6, 2009, found in 

compliance
6

Procedure

Safety and function testing may involve some risk to personnel and to equipment. NREL 

endeavors to accomplish its tasks with minimal risk by incorporating appropriate controls into 

testing procedures. This test report documents these controls where they may have had an 

influence on results obtained.

Control and Protection System Functions

The first part of the test procedure is to assess the control and protection system functions 

listed below. For each function, NREL provided an input to the existing control and 

protection system or simulated the external condition. NREL then recorded the response of 

the turbine.

In the list below, turbine response was observed for each major response category (startup, 

normal shutdown, emergency shutdown). If faults or other actions caused one of these major 

responses, NREL simulates the appropriate input and verifies that the control and protection 

system appropriately a) sensed the condition, and b) provided indication of an appropriate 

response. This procedure enables, for example, all the E-stop functions to be checked without 

exposing the turbine to multiple, potentially-damaging stops. These checks are designated by 

the term “behavior” in the list below.

1. Power control

2. Rotor speed control

3. Yaw orientation

4. Startup

a. Normal operation – winds rising above cut-in

b. After maintenance or fault clearance at design wind speed or above

c. Maintenance of fault conditions at design wind speed or above

5. Normal shutdown

6. Emergency shutdown during operation

7. Behavior upon excessive vibration

8. Behavior upon loss of load

9. Turbine specific checks

a. Behavior upon over-temperature

b. Behavior upon loss of load brake or diversion load connection
7

Personnel Safety Provisions

The second part of the test procedure is to evaluate provisions for personnel safety. For this 

turbine, the following issues were reviewed.

• Safety instructions 

• Climbing 

• Fire resistance and control

• Fire extinguisher

• Emergency stop buttons

• Lock-out / tag-out provisions

• Interlock on electrical cabinets

• Safety signs

• Unauthorized changing of control settings

• Lightning protection

• Presence and functioning of rotor and yaw lock

Dynamic Behavior

NREL observed the turbine over a wide range of wind speeds. Observations were written in 

the logbook and are reported in the results section. No direct measurement of accelerations 

was done for this turbine.

Results

Test results reported here are based on test conducted from June 12, 2008 when the turbine 

was commissioned through October 2, 2009.

Control and Protection System Functions

The only significant finding is that the rotor speed NREL measured is well above what the 

manufacturer specified.

NREL limits testing to investigate single-fault failures and has not investigated failures of 

“safe life” components. If a second fault were to occur during a critical event, severe results 

can be expected. NREL does not make judgments on whether such failures are likely or 

whether additional features in the control and protection system are needed to protect against 

such consequences.

The following is a list of tests that NREL conducted on the ARE 442:
8

Power control

Figure 3 shows that the power output of the turbine system is limited. This is mainly due to 

the power output limitations of the inverters. It does not necessarily mean that the turbine 

itself is limiting power correctly. The measured power curve does not deviate significantly 

from the published power curve.

Rotor speed control

Rotor speed measurements taken during the test period do not conclusively indicate that the 

turbine system exhibits control over rotor speed in response to high winds. Figure 4 shows 

both 10-minute average rotor speed data and maximum and minimum value in each 10 minute 

period. The maximum and minimum values are based on data samples at 40Hz. The averages 

appear to be leveling off quite well. However, there is quite a bit of variation in the maxima 

with no clear trend. Most of the high maxima were measured during periods where the turbine 

came back online from a faulted condition during high wind conditions. An example of such a 

high rotor speed event is given in Figure 5. 

The manufacturer’s expected maximum rotor speed was “above 200 rpm.”

Yaw orientation

NREL observed yaw behavior frequently during the test period and compared yaw position 

with the nearby wind-vane indication of wind direction. We observed normal behavior under 

all wind conditions. At low wind speeds, the rotor operates at about 40° offset from the 

prevailing wind direction. This yaw error decreases as the wind speed increases until the 

turbine furls.

This turbine uses slip rings to transmit power to and from the nacelle to the tower cable. 

Therefore, droop cable over-twist is not an issue.

Startup

NREL observed that the turbine rotor starts spinning whenever winds increase to about 2 m/s. 

The turbine controller responds after a wait period during which it checks brake functionality. 

This is followed by a period during which the controller keeps the rotor speed at a low value 

until the inverters come on-line. When the inverters are online, the controller releases the 

rotor to normal operating speed. NREL has observed the turbine starting up over a wide range 

of wind speeds. NREL has not observed any abnormal behavior during any of the startups.

NREL observed similar smooth cut-ins when the turbine was returned to service after 

shutdown.

Normal Shutdown

When winds drop below cut-in, the rotor gradually slows and stops producing power with no 

significant change in sound or behavior. This turbine does not have a cut-out wind speed, so 

normally it does not shut down in high winds.

Emergency shutdown during operation from any operating condition

Physically the emergency shutdown is the same as an automatic shutdown due to a fault.
9

The turbine safely brings the rotor down to an idling speed under any wind condition. This 

behavior is consistent with the manual’s statement that the system can be shut down at any

wind speed.

In addition to the automatic shutdown the controller performed, NREL also performed 

shutdowns by pushing the stop button on the voltage clamp. The turbine safely brought the 

rotor down to an idling speed any time this was performed.

Behavior upon excessive vibration

The turbine has no means to sense excessive vibration or to shut down should excessive 

vibration occur. The IEC turbine design standards require such sensors on large turbines but 

not on turbines smaller than 200m2

Behavior upon loss of load

.

When the inverters sense a grid fault, they disconnect from the grid. The voltage clamp then 

applies the brake. NREL tested for this by opening the disconnect switch between the ARE 

subpanel and panel 3-3L. This test took place on November 5, 2008 in winds of about 12 m/s.

The turbine shut down but then never came back online. It was found that the Insulated Gate 

Bipolar Transistors IGBT’s in the voltage clamp had failed. Figure 6 shows the time traces of 

the event.

A similar event during which the IGBT’s failed happened during a real grid outage on June 

13th. Both failures happened during winds in which the inverters were producing maximum 

power and the diversion loads were likely already active. 

On July 20, 2009, the loss of load simulation was repeated in low winds (6m/s). The turbine 

did not sustain any damage from this test. (Figure 7)

Turbine specific checks

Over temperature

This turbine system has provisions to monitor temperature in the voltage clamp and in the 

diversion loads. Should those components become too hot, the turbine shuts down, initiates a 

5-minute cool down period, and waits until all temperatures are below their set point. On 

December 5, 2008, independent temperature readings were taken during high winds. At the 

time, an over-temperature fault occurred. NREL measured the temperature at the top of one of 

the diversion loads to be 72.7°C. The temperature in the voltage clamp enclosure was 41.2°. 

At that time, the ambient temperature in the data shed was 34.4°C.

Load brake resistor failure simulation

Upon startup of the turbine, the voltage clamp checks to see if the diversion loads and brake 

resistors are properly installed. To test this function, NREL disconnected the DL2+ wire 

inside the voltage clamp. The turbine went through the startup sequence, allowing the rotor to 

rotate slowly. It then faulted to a Load/Brake Resistor test fault as indicated by the red and 

green LED both being steady on.
10

Personnel Safety Provisions

Safety Instructions

The turbine operator’s manual provides few safety instructions for installation, operation, and 

maintenance. The turbine does not require trained personnel for maintenance or servicing so 

no warning of this nature is required on the manual’s cover.

The Owners manual covers assembly of the turbine but not the actual installation of the 

turbine system. NREL asked and received a separate document describing the installation 

procedure including hoisting and rigging information. 

NREL checked the manual to determine if the safety instructions addressed requirements in 

the IEC small turbine design standard and found the following:

1. Disengage the load and/or energy sources: The voltage clamp has instructions 

indicating that it should only be opened after the stop button has been pushed. 

The inverter manuals describe how to disconnect the inverters from both the DC and 

AC connections.

2. Stop and secure the rotor: NREL found an explanation on how to slow down the rotor 

but no provision was found on how to stop it completely.

3. Stop and secure the yaw mechanism: The turbine has no provisions for securing the 

yaw mechanism.

4. Stop and secure the furling system: The turbine has no provisions for securing the furl 

mechanism.

5. Climb tower: The tower came with a TUF TUG safety climb system. It included a 

manual with instructions for safe climbing. 

Climbing

NREL personnel climbed the turbine using the supplied TUF TUG fall protection system. On 

one side of the tower, additional horizontal braces are installed to form a ladder. Climbing the 

tower was found to be fairly easy. The main issue was getting to a working position at the top 

of the climbing system. There are no recommendations in the owner’s manual about 

transferring from the fall protection cable to a working position on the turbine and the 

climbing system ends before reaching a position high enough to work on the turbine. There 

are no obvious or clearly identified tie off points other then the tab on top of the turbine 

behind the rotor, which is difficult to reach when still holding on to the side of the ladder. 

Another issue is preventing the turbine from yawing while in the process of getting into a 

working position. NREL recommends inserting some language into the manual describing

how to safely tie off a blade to the tower to prevent rotor rotation and yaw movement. 
11

Fire resistance and control

The Windyboy inverters are designed to resist “normal internal temperatures” and according 

to the manual will de-rate to maintain safe internal temperatures. NREL did not evaluate this 

since the inverter is UL listed as compliant with UL 1741. 

The voltage clamp has a temperature sensor which will shut the turbine down once the 

temperature exceeds a threshold. The dump load is enclosed in a fire-resistant, metal 

enclosure. It has temperature sensors installed in the top of the enclosures. If the temperature 

exceeds the limits, the turbine will shut down.

The turbine Owner’s Manual describes the clearance required around each of the system’s 

components.

Fire extinguisher

NREL provided a fire extinguisher in the building that housed the voltage clamp, diversion 

loads, and inverters. The manufacturer does not provide fire extinguishers or recommend that 

they be installed.

Emergency Stop Button 

The turbine has an emergency stop button on the voltage clamp (Figure 8) for use in manual 

turbine shutdown.

Lock-out / tag-out provisions

NREL provided a lockable switch between the grid and the subpanel that was connected to 

the voltage clamp and the inverters (Figure 9). The manufacturer does not provide this 

equipment or recommend that this type of equipment be installed. Nor does the manufacturer 

provide procedures for de-energization of the turbine system.

Interlock on electrical cabinets

The voltage clamp does not have an interlock on the cabinet. However, there is a warning 

label and instructions on the door. A hex key is needed to open the cabinet.

Safety signs

1. The voltage clamp has a label warning of high voltage and instructions on how to 

safely open the enclosure. (Figure 10)

2. The diversion loads did not have any warning signs. NREL added a sign stating 

“Caution hot surface do not touch.”

3. The TUF TUG safety system has a tag on the cable at the base of the tower. (Figure 

11)

4. NREL added labels indicating the voltage levels on all enclosures, electrical panels,

and disconnects.

Unauthorized changing of control settings

There are no readily accessible ways to alter any settings in the voltage clamp. The inverter 

settings can be changed if the directions in the manual are followed. The inverter must be

opened to do so. 
12

Lighting Protection

The turbine was purchased with the lightning protection package. This is normally an add-on 

that has to be purchased separately. It consists of three surge suppressors. One at the tower 

base, one on the voltage clamp, and one on the sub-panel as indicated in Figure 2. During the 

test period, no direct or nearby lightning strikes were observed. 

In addition to the surge suppressors, the turbine base is grounded and a ground wire runs in 

the trench back to the data shed to a second ground rod. No Ufer ground was specified for the 

foundation itself.

Presence of rotor and yaw lock

There is no rotor lock or yaw lock present on the turbine. 

Dynamic Behavior

NREL observed operation throughout the test period in wind speeds ranging from dead calm 

to winds in excess of 25 m/s. The total observation time exceeded the required one hour. 

NREL did not measure accelerations directly. NREL noted that the turbine displayed no 

excessive vibrations. The turbine did not produce any significant differences in noise levels. 

Tail movement and yaw behavior appeared normal under all conditions.

Figure 3. Power response to wind speed (red- maxima, green - minima, blue -average)
13

Figure 4. Rotor speed response to wind speed (red- maxima, green - minima, blue -average)
14

Figure 5. Time series of a high rpm event (datafile ARE081230_001156)

0

5

10

15

20

25

30

35

40

250 260 270 280 290 300 310 320 330 340 350

Wind speed [m/s]

0

50

100

150

200

250

300

350

400

0

50

100

150

200

250

300

350

400

450

250 260 270 280 290 300 310 320 330 340 350

Rotorspeed [rpm]

Grid Voltage [V]

Rotorspeed

Grid voltage

-2000

0

2000

4000

6000

8000

10000

12000

14000

250 260 270 280 290 300 310 320 330 340 350

Power [W]

-1

0

1

2

3

4

5

6

250 260 270 280 290 300 310 320 330 340 350

Available [5 = available, 0 = 

unavailable]

Time [sec]
15

Figure 6. Turbine response during a simulated grid outage -- the IGBT’s failed. (datafile 

ARE081105_144425)

0

2

4

6

8

10

12

14

16

18

20

0 100 200 300 400 500 600

Wind speed [m/s]

0

50

100

150

200

250

300

0

20

40

60

80

100

120

140

160

180

200

0 100 200 300 400 500 600

Rotorspeed [rpm]

Grid Voltage [V]

Rotorspeed

Grid voltage

-2000

0

2000

4000

6000

8000

10000

12000

14000

0 100 200 300 400 500 600

Power [W]

-1

0

1

2

3

4

5

6

0 100 200 300 400 500 600

Available [5 = available, 0 = 

unavailable]

Time [sec]
16

Figure 7. Simulated grid outage in low winds (data file ARE090720_115146)

0

2

4

6

8

10

12

0 100 200 300 400 500 600 700 800

Wind speed [m/s]

0

50

100

150

200

250

0

30

60

90

120

150

0 100 200 300 400 500 600 700 800

Rotorspeed [rpm]

Grid Voltage [V]

Rotorspeed

Grid voltage

-1000

0

1000

2000

3000

4000

5000

6000

7000

8000

0 100 200 300 400 500 600 700 800

Power [W]

-1

0

1

2

3

4

5

6

0 100 200 300 400 500 600 700 800

Available [5 = available, 0 = 

unavailable]

Time [sec]
17

Figure 8. ARE442 Voltage clamp with e-stop button
18

Figure 9. ARE 442 disconnect
19

Figure 10. Safety instructions on the voltage clamp
20

Figure 11. Safety instruction tag on the TUF TUG climbing system

Deviations and Exceptions

Deviations from the Standard

There were no known exceptions to the Standard for the test.

Exceptions to the NWTC Quality Assurance System

The data acquisition modules were used beyond the calibration due date. The modules were 

post-test calibrated and found to be in compliance within the specifications. Appendix A 

includes the post-test calibration sheets.
21

Appendix A – Instrument Calibration Sheets 

Figure A.1. Power transducer calibration sheet
22

Figure A.2. Primary anemometer calibration sheet
23

Figure A.4. NI 9229 data acquisition module calibration sheet I
24

Figure A.5. NI 9217 data acquisition module calibration sheet I
25

Figure A.6. NI 9205 data acquisition module calibration sheet I
26

Figure A.7. NI 9229 data acquisition module calibration sheet II
27

Figure A.8. NI 9217 data acquisition module calibration sheet II
28

Figure A.9. NI 9205 data acquisition module calibration sheet II
F1147-E(10/2008)

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PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE (DD-MM-YYYY)

February 2010

2. REPORT TYPE

Technical Report

3. DATES COVERED (From - To)

4. TITLE AND SUBTITLE

Wind Turbine Safety and Function Test Report for the ARE 442 

Wind Turbine

5a. CONTRACT NUMBER

DE-AC36-08-GO28308

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

J. van Dam, D. Baker, and D. Jager

5d. PROJECT NUMBER

NREL/TP-500-47030

5e. TASK NUMBER

WE102211

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-500-47030

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 as part of the U.S. Department of Energy’s (DOE) 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, four turbines were tested at the National Wind Technology Center (NWTC) as a part of this 

project. Safety and function testing is one of up to five tests that were performed on the turbines, including power 

performance, duration, noise, and power quality tests. Test results provide manufacturers with reports that can be 

used for small wind turbine certification. The test equipment includes an ARE 442 wind turbine mounted on a 100-ft 

free-standing lattice tower. The system was installed by the NWTC Site Operations group with guidance and 

assistance from Abundant Renewable Energy. 

15. SUBJECT TERMS

ARE 442 wind turbine; safety and function test; independent testing project; small wind turbines

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)

Prescribed by ANSI Std. Z39.18