Xylem H-375 04101 WIND MONITOR-JR - Manual (Page 2)

Page 1
WIND SPEED SPECIFICATION SUMMARY
Range 0 to 60 m/s (130 mph), gust survival
100 m/s (220 mph)
Sensor 13 cm diameter 4-blade helicoid pro-
peller molded of polypropylene
Pitch 29.4 cm air passage per revolution
Distance Constant 2.0 m (6.6 ft.) for 63% recovery
Threshold Sensitivity 1.0 m/s (2.2 mph)
Transducer Centrally mounted stationary coil, 2K
Ohm nominal DC resistance
Transducer Output AC sine wave signal induced by
rotating magnet on propeller shaft.
40 mV p-p at 100 rpm. 4.0 V p-p
at 10,000 rpm.
Output Frequency 3 cycles per propeller revolution
(0.0980 m/s per Hz)
WIND DIRECTION (AZIMUTH) SPECIFICATION SUMMARY
Range 360° mechanical, 352° electrical
(8° open)
Sensor Balanced vane, 21 cm (8 in)
turning radius.
Damping Ratio 0.3
Delay Distance 0.8 m (2.6 ft) for 50% recovery
Threshold Sensitivity 1.7 m/s (3.8 mph) at 10° displacement
Transducer Precision conductive plastic poten-
tiometer, 10K ohm resistance (±20%),
1% linearity, life expectancy 50 mil-
lion revolutions, rated 1 watt at 40° C,
0 watts at 125° C
Transducer Excitation
Requirement
Regulated DC voltage, 15 VDC max
Transducer Output Analog DC voltage proportional to
azimuth angle with regulated excita-
tion voltage applied across potenti-
ometer.
MODEL 04101
WIND MONITOR-JR
GENERAL
Operating Temperature -50 to 50°C (-58 to 122 °F)
INTRODUCTION
The Wind Monitor measures horizontal wind speed and direction.
Originally developed for ocean data buoy use, it is rugged and
corrosion resistant yet accurate and light weight. The main
housing, nose cone, propeller, and other internal parts are
injection molded U.V. stabilized plastic. Both the propeller and
vertical shafts use stainless steel precision grade ball bearings.
Bearings have light contacting teflon seals and are filled with a
low torque wide temperature range grease to help exclude
contamination and moisture.
Propeller rotation produces an AC sine wave signal with fre-
quency proportional to wind speed. This AC signal is induced in
a stationary coil by a six pole magnet mounted on the propeller
shaft. Three complete sine wave cycles are produced for each
propeller revolution.
Vane position is transmitted by a 10K ohm precision conductive
plastic potentiometer which requires a regulated excitation
voltage. With a constant voltage applied to the potentiometer, the
output signal is an analog voltage directly proportional to wind
direction angle.
The instrument mounts on standard one inch pipe, outside
diameter 34 mm (1.34"). An orientation ring is provided so the
instrument can be removed for maintenance and reinstalled
without loss of wind direction reference. Both mounting post
assembly and orientation ring are secured to the mounting pipe
by stainless steel band clamps. Electrical connections are made
in a junction box at the base. A variety of devices are available
for signal conditioning, display, and recording of wind speed and
direction.
INITIAL CHECKOUT
When the Wind Monitor is unpacked it should be checked
carefully for any signs of shipping damage. The instrument is
aligned, balanced and fully calibrated before shipment, however
it should be checked both mechanically and electrically before
installation. The vane and propeller should easily rotate 360°
without friction. Check vane balance by holding the instrument
base so the vane surface is horizontal. It should have near
neutral torque without any particular tendency to rotate. A slight
imbalance will not degrade performance.
The potentiometer requires a stable DC excitation voltage. Do not
exceed 15 volts. When the potentiometer wiper is in the deadband
region, the output signal is “floating” and may show varying or
unpredictable values. To prevent false readings, signal condi-
tioning electronics should clamp the signal to excitation or
reference level when this occurs. Note: Young signal condi-
tioning devices clamp the signal to excitation level. Avoid
a short circuit between the wind direction signal line and either
the excitation or reference lines. Damage to the potentiometer
may occur if a short circuit condition exists.
Before installation, connect the instrument to an indicator as
shown in the wiring diagram and check for proper wind speed
and wind direction values. Position the vane over a sheet of
paper with 30° or 45° crossmarkings to check vane alignment.