MODEL 012
VERTICAL WIND SPEED SENSOR
OPERATION MANUAL
DOCUMENT 012-9800
1600 Washington Blvd.
Grants Pass, Oregon 97526
Telephone 541-471-7111
Facsimile 541-471-7116
Met One
Instruments
Regional Sales & Service
3206 Main St., Suite 106
Rowlett, Texas 75088
Telephone 972-412-4715
Facsimile 972-412-4716
DESCRIPTION
The Gill Propeller Anemometer is a sensitive
precision air speed measuring instrument employing a foamed polystyrene propeller molded
in the form of a true helicoid. The propeller
provides one revolution for each 30 centimeters
of passing wind. Extensive wind tunnel tests
have shown that the propeller has a very linear
response for all wind speeds above 1 meter per
second (2.2 mph). Some slippage occurs just
above the threshold speed of 0.2 meters per
second (0.4 mph) however the calibration formula does not have a significant zero offset.
(Most anemometers have a zero offset) .
In the standard instrument the propeller drives
a miniature d.c. tachometer generator providing
an analog voltage output which is directly proportional to wind speed. The signal is suitable
for most millivolt recorders and several types
of galvanometer recorders. The output voltage
is 500 mV at 1800 rpm (417 mV at 1500 rpm) and
is linear from zero rpm through this calibration
point and above to full scale. Internal re~"*
. .'
sistance of the miniature generator is 32 ohms.
An optional generator is available which provides 2400 nV at 1800 rpm (2000 mV at 1500 rpm)
if a higher level output signal is needed.
A photo chopper transducer is also available as
an option where a digital output is desired.
Separate photo chopper instructions are added
following this section if this-option has been
ordered.
The Propeller kl~mometer will measure beth forward and reverse air flow. When the propeller
rotation reverses the generator si~nal polarity
reverses; thus the meter or recorder can be
calibrated to read both plus and minus from a
center zero position. Only two conductors are
required to connect the sensor.
The propeller responds only to that component
of the wind which is parallel with its axis of
rotation. When the wind is exactly perpendi-
cular to the axis of the propeller it will stop
rotating altogether. The propeller response as
a function of its orientation to the wind closely approximates the cosine law (refer to the
propeller response curve). This makes the instrument especially suited for measurements of
the vertical wind component. It should be
pointed out that the largest and most sensitive
propeller, 23cm diameter X 30cm pitch, is intended for applications requiring very low
threshold ~nd maximum low speed response. Its
range is from threshold to 30 mls (70 mph) in
axial flow, or 22 mls (50 mph) in all angle
flow. Note that higher wind speeds may cause
propeller failure. The 19cm diameter propeller
has a greater working range with only slight
sacrifice in threshold sensitivity. Its range
is greater than 40 mls (90 mph) axial flow and
30 mls (70 mph) all angle flow.
The 15cm diameter polystyrene propeller is intended for applications requiring exposure to
high winds and 10ngeI intervals of unattended
operation. A new 18cm X 30cm pitch injection
molded polypropylene propeller is also available
for applications which requir~ greater durability at some sacrifice in threshold and frequency
response.
For the most critical applications, an optional
propeller extension is availlble which improves
the response of the instrument at low wind
speeds. This extension is the same diameter as
the front section of the instrument and Rpproximately 6cm (2.4 inches) long. It is instalicd
in place of the propeller nut and propeller button so that the physical configuration of the
sensor is symmetrical on each side of the propeller. The extension improves the low speed
response in the stall region (90 0 wind angle)
by reducing the stall angle and by providing
better symmetry of response each side of stall.
INSTALLATION AND CALIBRATION
such as meters per second, miles per hour, or
The Propeller Anemometer is supplied with a
feet per second.
~b
mounting fitting so that it can be mounted on
3/4 inch standard iron pipe.
The sensor is
The output signal contains a ripple voltage
connected both mechanically and electrically to
caused by the brushes switching between seg-
the mounting fitting with an MS type cable
ments of the commutator of the d.c. generator.
connector so that it can be quickly and easily
For some high speed data loggers it may be de-
removed from its mounting when not in use.
sirable to filter the signal to remove
A
~his
dust cap is provided so the connector on the
ripple.
mounting fitting can be covered when the sensor
accomplished by connecting a 500 to 1000 mfd
is removed.
(lOV) electrolytic capacitor directly across the
Satisfactory filtering can usually be
output signal.
If the signal will be bipolar
If the instrument is to be installed in loca-
two capacitors should be used in series with the
tions which are subject to occasional high winds
negative leads connected together and the posi-
or where it will be left for extended periods
tive leads connected across the output signal.
without attention, i t is recommended that the
This will provide an RC filter of about .01 -
collar of the cable connector be safety wired
.02 second time constant which will not signifi-
or taped to eliminate the possibility of loosen-
cantly affect the accuracy of the output signal.
ind due to vibration.
The generator housing
The time constant can be increased by adding
threaded collar and the threaded joint between
more capacitance or by adding resistance each
the generator housing and shaft housing should
side of the capacitor.
also be tightened securely and taped to prevent
of the filter will be governed by the nature of
loosening.
the data logging equipment to be used.
Just under the propeller hub are several holes
Calibration generally requires one man on the
equnlly spaced around the housing.
tower while another makes the signal level ad-
An air pas-
da~a
The final configuration
sage has been provided through the cable connec-
justment at the
tor and within the sensor to by-pass the rear
propeller, propeller button and hub from the
bearing and generator.
sensor.
This air passage allows
station.
First remove the
The flexible drive coupling of the
the sensor to be purged with filtered air or
synchronous motor Calibrating Unit can then be
inert gas which is continuously expelled through
slipped onto the shaft of the sensor with the
the air holes under the propeller hub.
This is
slot in the coupling engaging the two flats on
recommended when the sensor is mounted outdoors
the propeller shaft.
in positions other than vertical to prevent rain
then turned on first to rotate counterclockwise
The Calibrating Unit is
and ·wind blown dust particles from entering the
representing air flow from the front of the
front bearing and other parts of the sensor.
sensor and indicating positive on the recorder.
Purging is also recommended for all mounting
Next the Calibrating Unit is switched to clock-
positions when the installation is in an ex-
wise rotation representing reverse or negative
tremel~
air flow.
dusty or corrosive atmosphere.
Be careful to maintain reasonable
alignment and avoid excessive end pressure so
Calibration of the Propeller Anemometer output
that the sensor bearings do not receive unneces-
signal is normally accomplished after install-
sary end or radial thrust during the calibration
ation by driving the sensor at a known rpm with
procedure.
When the instrument is to be used
the synchronous motor Calibration Unit and ad-
for vertical wind measurements it is generally
justing the voltage level to correspond to the
desirable to reverse the sensor connections so
desired reading for that speed.
Since the
standard signal output is an analog voltage it
is easily adjusted with a trimming potentiometer to read directly in engineering units
that a downdraft
, , will provide a negative signal
with the propeller mounted upward.
Three different speed Calibrating Units are
available. Calibration values are calculated
as follows (when operating on 115 volts/GO Hz.)*:
CAT. NO. 27230
180g
~pm/60
~ps
30
CALIBRATIN~
equals: 30
X 0.3
mete~s pe~
UNIT - 1800 rpm
~evolutions pe~
second
revolution (30cm pitch)
equals:
9.0 meters per second
(or 20.1 miles per hour. 29.5 feet per second)
CAT. NO. 27231 CALIBRATING UNIT - 300 rpm
300
~pm/60
equals: 5 revolutiona per second
5 rps X 0.3 meters per revolution (30cm pitch)
equals:
1.5 meters per second
(or 3.4 miles per hour. or 4.9 feet per second)
CAT. NO. 27232 CALIBRATING UNIT - 3600 rpm
3600 rpm/60 equals: 60 revolutions per second
60
~ps
EXPOSURE
The exposure of the Propeller Anemometer to get
representative wind data is very important.
Eddies in the lee of bUildings, trees, or other
obstr.uctions can greatly reduce the value of
observations. Unless it is desired to actually
measure the eddy effect of buildings or other
structures, it will be desirable to locate the
instrument well above or to the windward of such
obstructions. As a rule of thumb. the normal
flow Of air past a cubical structure will disturb the air flow about twice the height of the
structure to windward; six times the height to
leeward; and up to twice the height above the
ground.
X 0.3 meters per revolution (30cm pitch)
equals:
18.0 meters per second
(or 40.3 miles per hour. 59.1 feet per second)
These values are for full range calibration of
the 19cm diameter polystyrene propeller. For
low range calibration, vertical calibration, or
15cm and 23cm diameter propellers refer to the
PROPELLER SPECIFICATIONS and PROPELLER CALIBRATION-WIND SPEED VS PROPELLER RPM which follow.
The Propeller Anemometer should normally be
mounted with the propeller facing the prevailing wind direction. For vertical measurements
the propeller should be mounted upward. This
will minimize the chance of moisture or dirt
entering the working parts of the instrument
around the propeller hub.
If the 18cm X 30cm polypropylene propeller is
to be used refer to the separate specifications
and calibration curves provided.
When the instrument is used for vertical wind
component measurements a slightly different
calibration provides improved results. Because
normal unobstructed wind flow infrequently exceeds ± 30 degrees from the horizontal a 1.25
correction factor applied to the signal output
brings the propeller response much closer to
the cosine law within this range. With the
meter or recorder adjusted to read 11.3 mls at
1800 rpm, or 2.03 mls at 300 rpm, propeller
response (19cm diameter) follows the cosine law
within ± 3% in the range of 60° to 120° (± 30°
each side of stall). Since the standard deviation of elevation angle of the wind in open
terrain rarely exceeds 12 degrees, about 98% of
observations will be within ± 30 degrees (2~
standard deviations). Refer to curve of PROPELLER RESPONSE - VERTICAL WIND COMPONENT.
~
DISASSEMBLY AND SERVICE
The propeller is mounted on a stainless steel
shaft which turns in precision instrument grade
stainless steel ball bearings. These bearings
are double shielded to help prevent dust or
other foreign material from getting into the
precision balls and raceways. Since low tor~ue
is essential to good performance, extreme care
should be exercised when disassembling the i~­
strument to keep the bearings from being co~­
taminated.
Experience has shown that it is usually impractical for the average instrument technician to
attempt to thoroughly clean and satisfactorily
relubricate these If,iniature precision bearings.
Life expectancy of these bearings in normal use
is 3-6 years. , ,In especially dusty or corrosive
environments this life expectancy will be re-
Calibrating units can also be operated on 115 volts/50 Hz however. rpm (synchronous speed) and
equivalent
calib~ation
values are reduced to 5/6 of the values shown.
See PROPELLER
SPECIFICATIO~S.
duced. It is intended that when bearing friction becomes noticeable new bearings will be
reordered and installed. Bearings are easily
replaced. First remove the propeller and propeller hub. The front bearing is covered by a
plastic dust shield which is removed to gain
acceSR to the front bearing and a stainless
steel retaining ring ("E" ring) which fits a
groove in the propeller shaft. Removing this
retaining ring will allow the propeller shaft
to slide out through both front and rear bearings. Old bearings can then be. removed with
the aid of a pocket knife and new ones inserted
in the housing. Care should be exercised to
avoid excessive pressure on the new bearings
during reassembly. After reassembly the propeller shaft should be checked, and adjusted if
necessary, to provide an end play of approximately 0.31lUR.
(0.010 inch).
The miniature tachometer generator has a life
expectancy in excess of 1000 million revolutions
which represents 3-4 years of normal operation.
When generator voltage output becomes erratic
(usually due to brush failure) or begins to
show signs of bearing failure the entire generator assembly should be removed and replaced.
It is generally impractical to attempt to dis-
assemble and recondition the generator.
The plastic generator cell, which holds the
generator, can be removed from the instrument
by loosening the generator housing threaded
collar, then unsoldering the two generator leads
from the cable connector. The generator cell
slips easily out of the rear of the generator
housing. The tachometer generator is simply a
friction fit in the generator cell and is easily
removed by pushing gently on the lead wire end
with a blunt rod. An ordinary pencil with an
eraser works well.
from the polystyrene propeller, the bearingsand the generator are the only components
in the sensor which are likely to require service or replacl~ment. Given reasonable care this
instrument should provide many years of service.
We hope it serves you well.
A~ide
'*
YOUNG
WIND SPEED vs VOLTAGE OUTPUT - mV
WIND SPEED vs PROPELLER RPM
9600
m/s
mph
Ips
knots
km/hr
8400
= 0.00490 x rpm
= 0.01096
0.01608 x rpm
0.00952 x rpm
0.01764 x rpm.
-
= 0.01764 x mV
= 0.03946 x mV
= 0.05789 x mV
m/s
mph
fps
knots
km/hr
x rpm
-
2500
0.03427 x mV
0.06350 x mV
\;;.
7200
2000
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6000
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1500 .....
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4800
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CALI BRATION POINTS
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1000 =>
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3600 RPM
3600
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3000 RPM ----D
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2400
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MODEL 08274 PROPELLER
500
WIND SPEED vs PROPELLER RPM
and
WIND SPEED vs VOLTAGE OUTPUT
1200
22 x 30 em EXPANDED POLYSTYRENE
a
a
10
20
30
40
50
60
70
80
WIND SPEED:
meters per second, miles per hour, feet per second, knots, kilometers per hour
• INSTALL PROPELLER SO THE PROPELLER SERIAL NO. FACES AWAY FROM THE SENSOR.
90
100
a
A08254.DWG
JULY 88
271200
.
PROPEllER S H A F T - - - - - - - - - - -
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27130B
27153A.
27128
GENERATOR HOUSING
GENERATOR HOUSING THREADED COLlAR
~ING.NEOPRENE
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27122
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FLANGE BEAAING- (2 REO:l)
27113A. OUST SHIE~ONT BEARING
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27111... PROPEI..I.£R
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~~_~'_m~
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~: :~~_~,_ m~""""
TOFrT
3:<" PIPE
l
FIBER THERMOP\-"SnC (OPTIONAL)
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271SM MOUNnNG FrrnNG f<SS'( (3/4' PIPE) WITH
(MS 3101...·20-155) RECEPTABLE
)
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_ _ __
i(0 --------=
271" SENSOR CONNECTOR (MS 31oeA-2G-15p)
271~'"
DUST CAl'
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GILL PROPELLER ANEMOMETER
MODEL 27106
GENERAL ASSEMBLY & REPLACEMENT PARTS
'*
R. M. YOUNG COMPANY
7101 AEIIIO 'A'U' DIIIIV!. T'IAVEIIISE CITY.IiAIC..41GAN
.'61.
REPlACEMENT PAATS (NOT SHOWN)
MOOEL27105 (OPTIONAL)
27122S
271304
271...
27150C
271528
FLANGE BEARING (SEALED)
GENERATOR HOUSING· 2400mV GENERATOR
GENERATOR CELL· 2400mV GENERATOR
PROPELLER EXTENSION· BLACK
D.C. GENERATOR (24OOmV) WITH COUPlING
PROPELLER ANEMOMETER Wl2400mV GENEIlI.TOR
--
'*
CALIBRATING UNIT
YOUNC
SYNCHRONOUS SPEEDS
-
MODEL 27231: 300 RPM 0 60Hz
H 250 RPM 0 50Hz
THE SYNCHRONOUS t.40TOR CALIBRATING UNIT IS A HAND HELD DEVICE USED
FOR CALIBRA nON OF WIND SPEED SIGNALS. THE FLEXIBLE TUBING IS COUPLED
TO THE SHAFT OF CUP TYPE OR PROPELLER TYPE ANEMOMETERS BY SUPPING
THE TUBING OVER THE SHAFT (WITH CUP WHEEL OR PROPELLER REMOVED).
FOR EARLIER MODEL SENSORS A PLAsnc COUPLING FITS ON THE END OF THE
TUBE AND ENGAGES THE TWO FLATS ON THE SHAFT.
MODEL 27232: 3600 RPM 0 60Hz
H 3000 RPM 0 50Hz
FOR 230 VAC OPERA nON, A 230 VAC MOTOR IS AVAILABLE WHICH IS
DESIGNA TED BY SUFFIX "H- AFTER THE MODEL NUMBER.
MODEL 27230: 1800 RPM 0 60Hz
H 1500 RPM 0 50Hz
MODEL 27233: 60 RPt.4
H 50 RPM
o
@
60Hz
50Hz
MODEL 27280:
600 RPM 0 60Hz
MODEL 27283:
1200 RPM 0 60Hz
27240A SYNCHRONOUS MOTOR
1800 rpm (BODINE #701)
27241A SYNCHRONOUS MOTOR
300 rpm (BODINE 6768)
27234C HANDLE ASSY
27242A SYNCHRONOUS MOTOR
3600 rpm (BODINE 6710)
27235B COVER~
27243A SYNCHRONOUS MOTOR
60 rpm (BODINE #772)
27248 SYNCHRONOUS MOTOR
600 rpm (HURST DPB600)
27254A TOGGLE SWITCH (CENTER OFF)
27249 SYNCHRONOUS MOTOR
1200 rpm (HURST DGA1200)
27250A MOTOR CAPACITOR
1.0 MFD (1800 & 3600 RPM)
27251A MOTOR CAPACITOR
1.5 MFD (60 & 300 RPM)
~S[NSOR
COUPLlNG
TUBE & SENSOR COUPING
(FOR SHAFT WITH MILLED
FLATS)
27258 AC LINE CORD ~
272358-02 COVER BRACKET
(2 REOD)
CONNECTION lJIAGRAu
THREADED BASE FOR MOUNTING
ON STANDARD CAMERA TRIPOD
27236C BASE ASSY
~[
-
II~
VAl'.
CAL/8RA nON UNIT
PROD: JUL Y 64
CfNrRAL ASSfMBLY & RfPLACfMfNT PARTS
f272JO
DWG: JUNf BB
R.M. YOUNG CO. TRAVfRsr CITY. MI 49684 U.S.A. 616-946-J9AO
References - Gill Propeller Anemometer I UVW Anemometer (listed In chronological order)
Holmes, A.M., Gill, G.C., and Carson, H.W., "A Propellor Type Vertical Anemometer," Journal of Applied Meteorology,
Vol 3, 1964, pp. 802.a04.
Drlnkrow, R., "A Solution to the Paired Gill-Anemometer Response Function," Journal of Applied Meteorology. Vol 11,
1972, pp. 76.a0.
Duchon, D.E., Brock, F.V., Armandarlz M., and Hom, J.D., "UVW Anemometer Dynamic Performance Study," ECOM5440, U.S. Army Electronics Command, 1970.
Hicks B.B., "Propeller Anemometers as Sensors of Atmospheric Turbulence," Boundary-Layer Meteorology, Vol 3, 1972,
pp. 214-228.
Horst, TW., "A Computer Algorithm for Correcting non-Cosine Response In the Gill Anemometer," BNWL-1651. Pt 1,
Battelle Pacific Northwest Laboratory, 1972.
Horst, T.W., "Corrections for Response Errors in a Three Component Anemometer," Journal of Applied Meteorology,
Vol 12, 1973, pp. 716-725.
FichU, G.H., and Kumar, P., "The Response of a Propeller Anemometer to Turbulent Flow With the Mean Wind Vector
Perpendicular to the Axis of Rotation," Boundary-Layer Meteorology, Vol 6, 1974, pp. 363-379.
Gill, G.C., "Development and Use of the Gill UVW Anemometer," Boundary-Layer Meteorology, Vol 8, 1975,
pp. 475-495.
McMichael, J.M., and K1ebanoff, P.S., "The Dynamic Response of Helicoid Anemometers," NBSIR 7S-n2, National
Bureau of Standards, 1975.
Bowers, A.J., and Teunlssen, HW., "Correction Factors for the Directional Response of Propeller Anemometers,"
MSRB- 84·1, Atmospheric Environment Service 1984. ~'