Young 27106 User Manual

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

GILL PROPELLER ANEMOMETER

MODEL 27106

R.M. YOUNG COMP ANY 2801 AERO PARK DRIVE, TRAVERSE CITY, MICHIGAN 49686, USA

TEL: [phone] FAX: [phone] WEB: www.youngusa.com

27106-90(E)

REV: E062309

MODEL 27106

GILL PROPELLER
ANEMOMETER

SPECIFICATION SUMMARY

Range, Axial Flow 0-30 m/s (70 mph)
Range, All Angles 0-25 m/s (55 mph)
Propeller 22 cm diameter 4-blade helicoid propeller,

expanded polystyrene
Pitch 29.4 cm air passage per revolution
Distance Constant* 1.0 m (3.2 ft.)
Threshold Sensitivity* 0.3 m/s (0.6 mph)

INTRODUCTION

The Gill Propeller Anemometer is a low threshold precision air velocity
sensor employing a fast response helicoid propeller. The instrument
uses a high quality tech-generator transducer which converts propeller
rotation to a DC voltage that is linearly proportional to air velocity. The
output signal is suitable for a wide range of signal translators and data
logging devices.

Airfl ow from any direction may be measured, however, the propeller
responds only to the component of the air fl ow which is parallel to the
axis of its rotation. Off-axis response closely approximates a cosine
curve (see accompanying graphs) with appropriate polarity. With
perpendicular air fl ow, the propeller does not rotate.

For detailed studies of low air speeds, optional propeller shaft
extensions improve response in the 90° stall region by improving
symmetry and reducing the stall angle.

The instrument mounts to 3/4 inch standard pipe. A rugged cable
connector provides both electrical and mechanical connection. A
dustcap is provided to protect the connector when the instrument is
removed.

INITIAL CHECKOUT

When the instrument is unpacked it should be carefully checked for
any signs of shipping damage. The propeller shaft should rotate easily
without friction.

Using the WIRING DIAGRAM as a guide, connect the instrument to
an indicator or voltmeter and check for proper signals from the sensor.
The calibration may be checked using the methods outlined in the
CALIBRATION section of this manual.

Signal Output Analog DC voltage proportional to axial wind

1800 rpm (500 mV) = 8.8 m/s (19.7 mph).
Power Requirement Anemometer is self powered.

Specifi cations represent nominal values determined in accordance with
ASTM standard procedures.

*

Threshold and Distance Constant values are for axial fl ow .

GENERAL

Operating Temperature: -50 to 50°C (-58 to 122°F)

component. Polarity reverses with reverse

rotation.

INSTALLATION

Generally, the instrument should be oriented with the propeller
facing the predominant fl ow of air being measured. In some cases
it is appropriate to orient the instrument so the predominant air fl ow
is perpendicular to the propeller such as in applications measuring
the vertical component of wind. Keep in mind that off-axis response
increases the effective threshold and distance constant.
For vertical measurements mount the instrument so the propeller faces
upward. This helps prevent moisture or dirt from entering around the
propeller hub and potentially contaminating the bearings.

If the instrument is used to measure high air velocity or left for extended
periods without attention, tape the threaded cable connector collar to
eliminate the possibility of loosening from vibration. The threaded joint
between the generator and shaft housings may also be taped.

For some applications commutator ripple from the tech-generator may
need to be reduced. Use a 500 uF 10 VDC non-polarized capacitor
connected across the sensor leads as shown in the wiring diagram.
Given the low internal resistance of the tech-generator the effective
time constant of this fi lter is approximately 15 mS and will not degrade
measurement accuracy to any signifi cant degree.

The instrument measures both forward and reverse air fl ow . Signal
polarity relative to the connection pins is shown in the wiring diagram.
In applications measuring horizontal air fl ow, most users connect
the sensor to produce a positive signal with fl ow from the front
(counterclockwise propeller rotation). In applications measuring vertical
air fl ow, the sensor is usually connected so downdrafts produce a
negative signal, updrafts a positive signal.

Output from the tech-generator should be connected to a load
impedance of 10k ohms or higher.

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27106-90(E)

CALIBRATION

Calibration is determined by propeller pitch and the output
characteristics of the tach-generator.

Both Model 08274 Expanded Polystyrene Propeller and Model 08254
Carbon Fiber Thermoplastic Propeller have a 29.4 cm/rev pitch. This is
equivalent to 0.0049 m/s per rpm and is accurate to ±1%. Zero offset
is insignifi cant. Formulas for other units of measurement appear on the
calibration chart included with this manual.

FLANGE BEARING REPLACEMENT

If anemometer bearings become noisy or wind speed threshold
increases above an acceptable level, bearings may need replace ment.
Check bearing condition using a Model 18310 Anemometer Bearing
Torque Disk. If, after replacing bearings, the torque is still too high,
check the tach-generator.

Replace bearings as follows:

The tach-generator output is set at the factory for 500 ±2 mV at 1800
rpm. Check the output by removing the propeller from the anemometer
and coupling an Anemometer Drive to the shaft. Check linearity
by taking measurements at several different speeds. If the tech­generator is out of calibration it must be replaced. See the following
MAINTENANCE section for details on replacement procedure.

Information on checking bearing and transducer torque, which can
affect propeller threshold, also appear in the MAINTENANCE section.

When the propeller is used for measuring vertical wind component,
users may want to apply a 1.25 multiplier to the output signal. This may
be done numerically in data processing operations or electronically
in the signal conditioning. Using the multiplier brings the anemometer
output signal within ±3% of the cosine response for elevation angles
between -30 and +30 degrees. Since the standard deviation of wind
elevation angle in open terrain rarely exceeds 12 degrees, 98% (2.5
standard deviations) of observations will be within ±30 degrees. Using
the multiplier is NOT necessary when the anemometer is used in a
UVW confi guration with YOUNG Model 26601 UVW Translator.

MAINTENANCE

Replace the tack-generator as follows:
Given proper care, the Gill Propeller Anemometer should provide

years of service. Components are conservatively rated and require
little maintenance. The only parts likely to need replacement due to
normal wear are the precision ball bearings and the tach-generator.
The replacement procedures are best performed in a service facility
and only by qualifi ed technicians. If service facilities are not available,
return the instrument to the factory.

Refer to the accompanying drawings to become familiar with part
names and locations.

PROPELLER

The Model 08274 Expanded Polystyrene (EPS) Propeller can be easily
damaged by careless handling, high winds, hail, or birds. Damage
from these causes is not covered by warranty. If the EPS propeller
is repeatedly damaged, consider using the more durable though
slightly less sensitive Model 08254 Carbon Fiber Thermoplastic (CFT)
Propeller.

1. REMOVE OLD BEARINGS
a) Remove propeller from anemometer.
b) Unthread and separate shaft housing assembly from
generator housing.
c) Loosen set screw on shaft collar/coupling disk and remove

from propeller shaft.
d) Slide propeller shaft through both bearings and out of
housing.
e) Pull front bearing dust shield off housing.
f) Using the edge of a pocket knife, gently pry front and rear

bearings out of housing.

2. INSTALL NEW BEARINGS
a) Gently insert front bearing into housing.
b) Push front bearing dust shield back onto housing.
c) Carefully slide propeller shaft through front bearing and into

housing.
d) Slide rear bearing over propeller shaft and gently push it into

housing.
e) Place shaft collar/coupling disk on propeller shaft.
f) Allow 0.010 inch (0.25 mm) end play gap between shaft
collar/coupling disk and bearing.

Tighten set screw (80 oz in, 5600 gm-cm max torque).

9) Thread shaft housing assembly into generator housing.
Tighten fi rmly.
h) Check bearing torque to confi rm it is within specifi cations.

TACH-GENERATOR REPLACEMENT

When the tach-generator output becomes erratic (usually due to
brush failure) or begins to show signs of bearing failure (high torque),
the entire generator assembly should be removed and replaced. If
replacing the tach-generator due to excessive torque make certain it is
indeed caused by a worn tach-generator, not the anemometer fl ange
bearings.

Replace the tach-generator as follows:

1. REMOVE OLD GENERATOR ASSEMBLY
a) Remove propeller from anemometer.
b) Unthread generator housing collar. Pull generator housing
away from sensor connector and generator assembly.
c) Note position of generator wires on sensor connector pins.

Unsolder wires from pins and remove old generator
assembly.

2. INSTALL NEW GENERATOR ASSEMBLY
a) Solder wires from new generator assembly onto proper
sensor connector pins. Verify correct polarity: CCW rotation

produces negative output voltage.
b) Slide generator housing over generator assembly. Firmly
tighten housing collar onto connector threads.
c) Check bearing torque to confi rm it is within specifi cation.

27106-90(E)

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