What is the exact definition of continuous duty?
The Regulation states that motors rated for continuous duty are covered. This means motors that are capable of continuous operation at their rated power with a temperature rise within the specified insulation temperature. Apart from motors rated for continuous operation (S1), other duty cycles to be considered as continuous duty are: S6, continuous duty with intermittent loads and S3, intermittent duty with a continuous duty factor of 80% or more. Duty types are defined in IEC 60034-1:2010 Rotating electrical machines – Part 1: Rating and performance.