As anemometer sensors operate in outdoor environments and are exposed to severe weather conditions, they deteriorate relatively quickly. To ensure stable, high-accuracy observation, anemometer maintenance should be carried out periodically. This section describes general points to note when performing maintenance and repairing the sensors of anemometers. Strictly speaking, it is not possible to repair anemometers on site. If cups, propellers or bearings that may affect rotation characteristics are serviced or repaired, the anemometer must be re-calibrated. In principle, repairs and calibrations must be carried out by the manufacturer or a Meteorological Instrument Center, where the various standard instruments and calibration/testing equipment necessary are available.
Maintenance and Repair of Anemometers
| Check item | Problem | Repair |
| External appearance | * Cup dents, arm deformation * Propeller deformation, wind-direction plate damage | * Badly deformed parts must be replaced. Slightly deformed parts can be repaired, but must be subjected to a rotational balance test. * It is not possible to repair such parts on site. Replacement is necessary. |
| Setup conditions | * Out-of-level mount * Wind-direction deviation | * Restore level status using a spirit level. * Orient the anemometer to the reference direction (usually north). |
| Unusual sounds | * Creaking sounds from rotary parts or lack of rotation at low wind speeds | * Bearings may be out of oil, worn or badly deformed. Dismantle the anemometer, clean bearings with gasoline and lubricate them. Bearings with significant wear must be replaced. * Overhaul the anemometer, clean all parts and lubricate them once a year. |
| Deterioration in sensitivity | * Wear on generator brushes or slip-ring contamination | * When overhauling an anemometer as described above, clean the brushes and slip rings. |
Other Points to Note
(1) Cable Damage Caused by Small Animals
On agricultural land such as forests and fields, small animals including field mice, rabbits and squirrels may damage cable coverings or even break cables. Accordingly, it is advisable to string cables high above the ground. If buried in the ground, they should be placed at a depth of 30 cm or more to avoid the leaf mold layer. In buildings too, the same precautions should be taken to guard against damage caused by mice.
(2) Clearing Snow and Ice
Snow and ice may adhere to anemometers in cold climates. If exposed to snow or low temperatures with no wind, rotating parts may become frozen. As anemometers may also be deformed by the weight of snow or ice, such build-up must be cleared periodically. It is advisable to provide artificial heating for anemometers operating in such environments.