Young Wind Sensor Calibration Accessories - Manual (Page 6)

Page 5
18860-90
MODEL 18802/18811
SELECTABLE SPEED
ANEMOMETER DRIVE
SPECIFICATIONS
Operating Range: 200 - 15,000 RPM (18802)
20.0 - 990.0 RPM (18811)
Resolution: 1 RPM (18802)
0.1 RPM (18811)
Power Requirement: 12 to 30 VDC (2W nominal, 6W
max)
Battery Power: Two 9-V
INTRODUCTION
The YOUNG Selectable Speed Anemometer Drive provides a
convenient and accurate way to rotate an anemometer shaft at a
known rate. The device consists of a control/display unit and a
variable speed motor with integral high-resolution optical encoder.
Two models are available: Model 18802 has an operating range
of 200 to 15,000 RPM for use with propeller type anemometers.
Model 18811 has a lower RPM range for use with cup type
anemometers. The control unit is the same in each case. High and
low speed motors are available separately, permitting operation in
both speed ranges with a single display unit.
The control unit automatically senses motor assembly type
(high or low speed) and adjusts display and controlling circuits
automatically. Operating parameters for each motor type include
MAX & MIN RPM, STEP SIZE, and 9 PRESET speeds. Settings
for these parameters are saved when power is off.
A front panel CW-CCW switch selects rotation direction (as seen
facing anemometer). Motor speed is selected using the UP-DOWN
keys. The display shows the target and actual RPM. Motor
rotation and measurement are referenced to a crystal oscillator for
stability and accuracy. Current limiting circuits protect the motor
from damage due to overload or stalling.
The 18802 is powered from an AC wall adapter (included). For
completely portable operation, two internal 9-V batteries power the
unit. Use lithium type for longest life. When batteries are low, the
controller stops the motor and alerts the user on the display.
OPERATION
For proper operation, the coupling on the motor must be
carefully aligned with the anemometer shaft. Misalignment,
particularly at low RPM rates, causes instability and stalling.
Alignment fixtures included with the device allow the motor to be
attached directly to YOUNG anemometers. Attach the alignment
fixture to the sensor as follows:
1) Remove propeller or cup-wheel from anemometer shaft and
attach coupling disc to shaft.
2) Mount clamp and bar fixture on sensor and gently tighten
clamp. Do not overtighten!
3) Attach motor to fixture. Carefully align anemometer and
motor coupling and gently tighten motor clamp. DO NOT
OVERTIGHTEN.
4) Turn unit ON and use the UP-DOWN keys to set target RPM.
5) Within several seconds display should show actual RPM
within ± 1 RPM of target setting. If not, carefully adjust
alignment until display shows proper value. This can be
performed while motor is running.
If the calibrating unit is used with an anemometer which does not
fit the alignment fixture, the motor may be held in place by hand.
Good results can be achieved if the motor and anemometer shafts
are well aligned.
MENU
Access the Setup Menu by pressing and holding the MENU key
for about five seconds. The motor will stop and the Setup Menu
will appear on the display. Each menu item and its function is listed
below.
Use the UP-DOWN keys to scroll between items on the menu list.
To EDIT a value, press the MENU key then use the UP-DOWN
keys to change it. When you are finished editing, press MENU
again. To return to OPERATE mode, repeatedly press the UP
key until OPERATE appears on the display then press MENU.
The 18802 stores the new settings and within several seconds
will begin operating at its lowest speed. You MUST return to
OPERATE mode to retain new settings.
MENU ITEM
DESCRIPTION
OPERATE Press MENU to return to OPERATE mode.
You MUST return to OPERATE
mode to retain new settings.
MAX RPM Maximum RPM allowed during operation.
Once the maximum is reached, pressing the
UP key has no effect. Limited to operating
range of motor.
MIN RPM Minimum RPM allowed during operation.
Once the minimum is reached, pressing the
DOWN key has no effect. Limited to operating
range of motor.
STEP SIZE The number of RPM added or subtracted
when the UP-DOWN keys are pressed to
change target RPM during operation.
PRESET YES/NO determines whether preset
RPM settings are used. If YES, pressing
the UP-DOWN keys selects preset speeds 1
through 9. If NO, UP-DOWN changes speed
by STEP SIZE increments.
PRESET1-9 Preset RPM values. Each PRESET may be
set to any value in operating range of motor.