What is the class of the 40 Anemometer?

The IEC Standard recommends certain cup classifications for anemometers to be used in power performance measurements (not wind assessment). Specifically, Annex I of IEC standard 61400-12-1 defines the general influence parameter ranges to use in the assessment of anemometer response deviations. The resultant maximum anemometer response deviation is the class number k.

Based on the report entitled “Accuwind -Classification of Five Cup Anemometers According to IEC 61400-12-1 (RIS-R-1556)” published by DTU Wind Energy Department (formerly RISO National Laboratory), the classification indices for the #40 Anemometer are 2.4A for Type A terrain and 7.7B for Type B terrain.