i
RFID Wind Turbine Test
Crosby Lab University of Maine, Orono, ME
Adam Freund, Amanda Mayette, and Matthew Sevey
4/13/2012
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Table of Contents
Introduction .................................................................................................................................... 1
Objectives........................................................................................................................................ 1
Apparatus, Equipment and Instruments ........................................................................................ 1
Theory ............................................................................................................................................. 3
Procedure ........................................................................................................................................ 4
Results ............................................................................................................................................. 8
Conclusions ................................................................................................................................... 11
Appendices.................................................................................................................................... 12
Appendix 1 – Summary of Wind Turbine Test Data ................................................................. 12
1
Introduction
The purpose of the experimental work is to determine the power output of a wind turbine of
unknown origin. The turbine for the experiment was provided to the group by Dr. Joe
Zydlewski, who is the Assistant Unit Leader-Fisheries at the Maine Cooperative Fish and Wildlife
Research Unit and Assistant Professor of Wildlife Ecology at the University of Maine. It appears
to be in good condition and would be expected to still reach its full output potential, however
paperwork was lost in the transition and there is no record of performance specifications.
The experiment consists of mounting the wind turbine in the wind tunnel located in Crosby Hall
Room 201. The turbine is tested at a variety of wind speeds and the power output (determined
from the voltage and current) is measured using LabVIEW. For each wind speed, the turbine will
be aligned such that the highest output possible is achieved. Using this data, a power curve for
the turbine will be produced and analyzed. The minimum power output that the turbine must
produce in order to be useable by Dr. Zydlewski is 24 W at a minimum of 24 VDC.
Objectives
1) Use LabVIEW to measure the voltage and current produced by the wind turbine at
various wind speeds. The current and voltage will be measured in DC amps and volts
respectively.
2) Determine the power output from the information gathered. Power is voltage times
current or resistance times current squared and will be given in watts.
3) Plot the power curve from the calculated information to be used as a tool for predicting
output at untested wind speeds.
4) Determine if the turbine will be a sufficient source to charge a 24 V battery bank that
needs to provide 24 W of constant power.
Apparatus, Equipment and Instruments
Table 1 - Apparatus, Equipment and Instruments
Name
Model #
Mastech Multimeter
Elenco Precision Power
Supply
Serial #
MAS830L
XP580
2N3055M0315
Info
(range, dimensions,etc)
2
Dataq Instruments
Isolated Volt Input
Module
DataForth Analog I/O
Backpanel
National Instruments 8Input Multifunction I/O
Low Current Sensor
Board
DI-5831-09
58010-27
Input: -40V to 40V
Output: -5V to 5V
SCMPB05
57074-11
Input: 5V DC, max
2800mA
USB-6009
14B003C
200mA Max
Input: 5V
Max Current: 5 Amps
DC/AC
Gain: 4.27-47
ACS712
Range: 0-500 
Adjustable Resistor
3 Phase Ac to DC
converter
Antec Computer with
LabVIEW
Alnor CompuFlow
CF8585
55060180
Wind Turbine
Blade Diameter: 48in
Wind Tunnel
8ftx8ftx20ft
Joy Manufacturing
Axivane Fan
38-26-1770AP
SF-53921
2300 cfm, Rated for
40hp, Max 50hp
Figure 1 shows the wiring set up for the experiment.
Data Acquisition
Modules
Figure 1 - Wiring for data acquisition
Figure 2 shows the electrical schematic of test setup.
Adjustable
Resistor
3
Figure 2 - Electrical Schematic
Figure 3 shows the wind tunnel and the locations of the fan, anemometer, and wind turbine.
Anemometer
Figure 3 - Wind Tunnel Set Up
Theory
Equation 1 shows how the power is determined from the measured voltage and current.
4
P= V*I=I2R
(1)
The voltage and current are measured, and recorded, using LabVIEW. The total resistance
applied to the turbine is measured using a hand held multimeter. A multimeter is also used to
measure the voltage and current to verify the LabVIEW data. The power is determined using
Equation 1.
Procedure
The first step is to adjust the fan speed by setting the fan blade angles to the desired setting.
Proper lockout procedure is required on the power box in the room, to prevent possible
injuries. The fan has seven blade positions, zero through six, but warning labels instruct users to
only use settings four through six. Setting six produces the lowest wind speed, with the wind
speed increasing as the setting number decreases. Figure 4 shows the fan blade settings.
3
0
6
Figure 4 - Fan Blade Settings
In order to adjust the blades, the protective grating on the back of the fan first must be
removed. To remove the grating, an 11mm wrench can be used to remove the bolts that hold it
on. After the grating is removed, the center cover can be removed using a 13mm wrench to
remove the six bolts holding the cover on. Figures 5 through 7 show the protective grating,
center cover, and the exposed blade bolts.
5
 Protective Grating
 Center Cover
Figure 5, 6, 7 - Protective Grating, Center Cover, Blade Bolts
To adjust the blades, a 1 ¼ inch socket is needed along with a torque wrench capable of 220 ftlbs. Each blade must be loosened, moved to the position required, and then tightened to 220
ft-lbs. Once the blades have all been adjusted, the center cover and the protective grating can
be reattached and the fan can be unlocked. Figure 8 shows the power box and lockout location.
Lockout
Figure 8 - Power box and lockout location
Before starting testing, it is necessary to ensure that all doors to the room are locked and that
the main door is bolted so that entry is impossible. Ear protection is required due to the
excessive noise made by the fan. Safety glasses should be worn because of possible flying
debris. Figure 9 shows the door securely latched.
6
Figure 9 - Door securely latched
Inside the tunnel is an anemometer for measuring the wind speed. It is extended towards to
center of the tunnel as far as possible and the cap on the end is removed. There is a safety
brake switch, which is switched to the brake position and then released after the LabVIEW
system is up and running. The brake switch works by shorts the three-phase voltage from the
turbine. This prevents the turbine from spinning when switched to the brake position. The
wiring for testing and data acquisition was primarily made by reassembling the setup created
by a previous group that designed and built the wind tunnel. The DataForth board is connected
to the computer by via the National Instruments USB Module so that LabVIEW can be opened
on the desktop to record the voltage and current. RPM can also be measured if desired,
provided the proper equipment is available. Figures 10 through 13 show the anemometer,
brake switch, wiring board, and computer stand.
Figure 10 and 11 - Anemometer and brake switch
Figure 12 and 13 - Wiring Board and Computer Stand
7
The fan is turned on by holding the lever in the “start” position until the fan has reached its
maximum speed (after approximately 45 seconds), and then quickly pushing the lever into the
“run” position. Once the fan is running, switch the safety switch off its brake setting. Wait for
the wind turbine blades to reach a steady state speed and for the LabVIEW data to level off
(approximately 30 seconds). Choose a file name and directory to save the data and then click
the RUN button on the screen. Each test will run for 60 seconds and will stop when the test is
complete. Switch the safety brake back on. During the minute run, hand voltage and current
measurements are taken to verify the LabVIEW data. The voltage reading is taken across the
resistor and the current reading is taken from the current sensor (in the form of a voltage signal
that must be converted) placed in series with the resistor. Alternatively, if two multimeters are
available, one multimeter can be left in series with the resistor to measure current. Figures 14
and 15 show the voltage and current hand measurement procedures, respectively.
Figure 14 and 15 - Voltage and Current Hand Measurements
This is repeated for 10 different settings of resistance, starting with the highest at 500  and
going down to 50  by 50  increments. It is important not to drop below 50  so that the
resistor does not burn out. This process will be repeated for each setting of blade position.
Figures 16 and 17 show how the resistance is adjusted.
8
50  increments
500 
50 
Figure 16 and 17 – Adjustable Resistance
Results
The output of the testing, as collected in LabVIEW, is displayed below in Figures 18 and 19.
These two figures show the voltage output vs. wind speed and power output vs. wind speed for
the turbine respectively.
From Figure 18, a clear correlation between the wind speed and the voltage exists. As the wind
increases in speed, the voltage increases as well. Since the voltage is directly proportional to
the power, it also suggests that the greater the wind speed, the higher the power output will
be. This is demonstrated in Figure 19 below. It is noted that the lower the resistive load applied
to the turbine, the higher the power output. This is due to the current increasing proportionally
as resistance decreases (Ohm’s Law). Since current has more effect on power than resistance (P
= I2R), lowering the resistance increased the power dissipated by the resistor. Appendix 1 is the
summarized table of data recorded while testing the wind turbine.
9
Figure 18 - Turbine Output Voltage vs. Wind Speed for Various Loads
10
Figure 19 - Turbine Power Output vs. Wind Speed for Various Loads
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Conclusions
After completing the testing of the wind turbine, it was determined that the wind turbine is not
a suitable power source to charge the battery bank. While it was found to be functional and
capable of generating the voltage needed to charge the 24 V battery bank, the power output is
not great enough to keep up with the required power once real world conditions are
considered. While the maximum power generated by the turbine slightly exceeds the required
power, this is for wind speeds much higher than are anticipated to be continuously blowing. It
is important to note that these results were achieved under a constant wind speed that is much
higher than the average wind speed of the potential installation area.
For a resistive load of 50, which is very similar to that of the system to be powered, the
maximum power obtained was 32.7 W. Since the maximum power output is close to the
required power output (24 W), wind that is slower or intermittent will result in a power output
significantly lower than required. For example, if the potential installation site has an average
wind speed of about 2 m/s, using the best fit power equation for a 50  load found in Figure 19
(P = 17.387(s)^0.2161) to provide a very rough estimate of the expected average power gives
an output of about 20 W. However, based on very similar wind turbines that were found online,
the expected startup wind speed, that is, the minimum wind speed required for the turbine to
generate any power, is about 3.2 m/s. Factoring in the inconsistency of wind, regardless of the
wind turbine’s capability, it will be unable to generate the power that the battery bank
requires.
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Appendices
Appendix 1 – Summary of Wind Turbine Test Data
Summary of Wind Turbine Test Data
Test
#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
Resistance
(Ω)
506
454
402
347
299
250
203
155
102
54.1
50.5
97.9
155.2
199.3
252
301
347
399
451
505
55.4
97.8
155
198.9
250
301
355
398
454
498
550
597
646
702
751
797
27.7
Avg
Calibrated
Voltage
(V)
Avg
Calibrated
Current
(A)
Power =
VI (watts)
37.422452
37.297245
36.919976
37.019175
36.691334
36.123319
37.304813
37.046642
38.453654
40.483224
43.387111
43.892088
41.670792
41.103691
45.548027
42.218755
42.766534
44.583106
47.909994
44.660656
46.183210
46.622960
47.279020
47.852656
48.506536
49.359507
50.553823
51.015885
52.420880
52.482170
53.803418
54.176289
54.437251
54.853771
55.130655
55.475797
50.759996
0.062901
0.069328
0.074234
0.086908
0.106697
0.126361
0.164223
0.220025
0.355096
0.704027
0.804633
0.429686
0.254637
0.253365
0.165456
0.125656
0.094827
0.098129
0.107260
0.073226
0.739952
0.442743
0.284272
0.220826
0.176510
0.145338
0.120534
0.104471
0.093089
0.084746
0.075505
0.071413
0.063043
0.055809
0.050920
0.048036
1.002939
2.353895
2.585754
2.740724
3.217260
3.914861
4.564571
6.126299
8.151191
13.654752
28.501290
34.910709
18.859823
10.610918
10.414219
7.536205
5.305048
4.055422
4.374877
5.138819
3.270328
34.173379
20.642006
13.440122
10.567104
8.561893
7.173830
6.093451
5.329702
4.879823
4.447656
4.062425
3.868883
3.431880
3.061323
2.807264
2.664808
50.909156
P=
I^2*R
(watts)
P=
V^2/R
(watts)
2.001983
2.182111
2.215306
2.620886
3.403901
3.991763
5.474730
7.503711
12.861528
26.814895
32.695445
18.075297
10.063155
12.793785
6.898693
4.752632
3.120280
3.842059
5.188609
2.707845
30.333141
19.170921
12.525677
9.699171
7.788953
6.358095
5.157592
4.343882
3.934190
3.576582
3.135549
3.044578
2.567465
2.186465
1.947242
1.839005
27.863034
2.767668
3.064063
3.390758
3.949335
4.502522
5.219577
6.855414
8.854540
14.496897
30.293742
37.276067
19.678400
11.188498
8.477237
8.232630
5.921672
5.270825
4.981587
5.089507
3.949652
38.499800
22.225976
14.421327
11.512703
9.411536
8.094222
7.199124
6.539248
6.052750
5.530880
5.263287
4.916366
4.587329
4.286234
4.047123
3.861435
93.017227
Average
Wind
Speed
(m/s)
8.41375
8.41375
8.41375
8.41375
8.41375
8.41375
8.41375
8.41375
8.41375
8.41375
13.0366
13.0366
13.0366
13.0366
13.0366
13.0366
13.0366
13.0366
13.0366
13.0366
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
16.5354
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Notes:
~For each test, the wind turbine was given time to reach steady-state conditions.
~After steady state was achieved, current voltage data was recorded for one minute using LabVIEW.
~A sampling rate of _ Hz was used, giving _ data points per test.
~These values were average and are displayed in the table above.
~Tests were performed with various resistive loads on the wind turbine.
~The fan blades were configured in three orientations to produce the wind speeds seen above.
~Due to the considerable fluctuations of wind speed produced by the wind tunnel, the high, low, and
median range of values were collected and averaged to produce the values in the table above.