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Anemometer Bearing Torque Disk (available from R.M. Young). If, after replacing bearings, the
torque is still too high, check the tach-generator.
If the bearings need to be replaced, have either Campbell Scientific or a qualified technician
replace them by using the following procedure:
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).
g. Thread shaft housing assembly into generator housing. Tighten firmly.
h. Check bearing torque to confirm it is within specifications.
8.1.2 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. Before replacing the tach-generator due to excessive torque, ensure it is caused by a
worn tach-generator, and not the anemometer flange bearings.
If the tach-generator needs to be replaced, have either Campbell Scientific or a qualified
technician replace it by using the following procedure:
27106T Vertical Propeller Anemometer
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