Table of Contents
Advertisement
and returned to its mounting without realigning the vane since the
orientation ring preserves the wind direction reference. Install the
Wind Monitor following these steps:
1. MOUNT WIND MONITOR
a) Place orientation ring on mounting post.
Do Not tighten band clamp yet.
b) Place Wind Monitor on mounting post. Do Not tighten band
clamp yet.
2. CONNECT SENSOR CABLE
a) Slide junction box cover up.
b) Route cable thru strain relief opening at bottom of junction box.
Secure cable by tightening packing nut.
c) Connect sensor cable to terminals. See wiring diagram.
d) Slide junction box cover down.
3. ALIGN VANE
a) Connect instrument to an indicator.
b) Choose a known wind direction reference point on the horizon.
c) Sighting down instrument centerline, point nose cone at
reference point on horizon.
d) While holding vane in position, slowly turn base until indicator
shows proper value.
e) Tighten mounting post band clamp.
f) Engage orientation ring indexing pin in notch at instrument
base.
g) Tighten orientation ring band clamp.
CALIBRATION
The Wind Monitor is fully calibrated before shipment and should
require no adjustments. Recalibration may be necessary after
some maintenance operations. Periodic calibration checks are
desirable and may be necessary where the instrument is used in
programs which require auditing of sensor performance.
Accurate wind direction calibration requires a Model 18112 Vane
Angle Bench Stand. Begin by connecting the instrument to a signal
conditioning circuit which has some method of indicating a wind
direction value. This may be a display which shows wind direction
values in angular degrees or simply a voltmeter monitoring the
output. Orient the base so the junction box faces due south.
Visually align the vane with the crossmarkings and observe the
indicator output. If the vane position and indicator do not agree
within 5°, it may be necessary to adjust the potentiometer coupling
inside the main housing. Details for making this adjustment appear
in the MAINTENANCE, POTENTIOMETER REPLACEMENT,
outline, step 7.
It is important to note that, while the sensor mechanically rotates
through 360°, the full scale wind direction signal from the signal
conditioning occurs at 355°. The signal conditioning electronics
must be adjusted accordingly. For example, in a circuit where
0 to 5.000 VDC represents 0° to 360°, the output must be
adjusted for 4.930 VDC when the instrument is at 355°.
(355°/360° X 5.000 volts = 4.930 volts).
Wind speed calibration is determined by propeller pitch and the
output characteristics of the transducer. The calibration formula
relating propeller rpm to wind speed is shown below. Standard
accuracy is ±0.2 m/s (0.4 mph). For greater accuracy, the sensor
must be individually calibrated in comparison with a wind speed
standard. Contact the factory or your supplier to schedule a NIST
(National Institute of Standards & Technology) traceable wind
tunnel calibration in our facility.
To calibrate wind system electronics, temporarily remove the
propeller and connect an anemometer drive (18802 or equivalent)
to the propeller shaft. Apply the calibration formula to the
calibrating motor rpm and adjust the electronics for the proper
value. For example, with the propeller shaft turning at 3600 rpm,
adjust an indicator to display 18.4 m/s [3600 rpm x 0.00512 (m/s)/
rpm = 18.4 m/s].
Details on checking bearing torque, which affects wind speed and
direction threshold, appear in the following section.
05305V-90(I)
CALIBRATION FORMULAS
Model 05305V Wind Monitor w / 08254 Propeller
WIND SPEED vs PROPELLER RPM
m/s
knots
mph
km/h
WIND SPEED vs 0-5 VDC OUTPUT
m/s
knots
mph
km/h
WIND DIRECTION vs 0-5 VDC OUTPUT
DEGREES
MAINTENANCE
Given proper care, the Wind Monitor should provide years of
service. The only components likely to need replacement due to
normal wear are the precision ball bearings and the wind direction
potentiometer. Only a qualified instrument technician should perform
the replacement. If service facilities are not available, return the
instrument to the company. Refer to the drawings to become familiar
with part names and locations. The asterisk * which appears in the
following outlines is a reminder that maximum torque on all set
screws is 80 oz-in.
POTENTIOMETER REPLACEMENT
The potentiometer has a life expectancy of fifty million revolutions.
As it becomes worn, the element may begin to produce noisy
signals or become nonlinear. When signal noise or non-linearity
becomes unacceptable, replace the potentiometer. Refer to
exploded view drawing and proceed as follows:
1. REMOVE MAIN HOUSING
a) Unscrew nose cone from main housing. Set o-ring aside
for later use.
b) Gently push main housing latch.
c) While pushing latch, lift main housing up and remove it from
vertical shaft bearing rotor.
2. UNSOLDER TRANSDUCER WIRE
a) Remove junction box cover, exposing circuit board.
b) Remove screws holding circuit board.
c) Unsolder three potentiometer wires (white, green, black), two
wind speed coil wires (red, black) and earth ground wire (red)
from board.
3. REMOVE POTENTIOMETER
a) Loosen set screw on potentiometer coupling and remove
it from potentiometer adjust thumbwheel.
b) Loosen set screw on potentiometer adjust thumbwheel and
remove it from potentiometer shaft.
c) Loosen two set screws at base of transducer assembly and
remove assembly from vertical shaft.
d) Unscrew potentiometer housing from potentiometer
mounting & coil assembly.
e) Push potentiometer out of potentiometer mounting &
coil assembly by applying firm but gentle pressure on
potentiometer shaft. Make sure that the shaft o-ring comes
out with the potentiometer. If not, then gently push it out
from the top of the coil assembly.
Page 2
=
0.00512 x rpm
=
0.00995 x rpm
=
0.01145 x rpm
=
0.01843 x rpm
=
mV x 0.0200
=
mV x 0.0389
=
mV x 0.0447
=
mV x 0.0720
=
mV x 0.072
Advertisement
Table of Contents
