Note
Motor duty types indicate the load that the motor drives, with sequential operations, involving startup,
electric braking, no-load running, power-off and stop.
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S1: Continuous duty
The operation of a motor at a rated load may take an unspecied time period to reach thermal
equilibrium.
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S4: Intermittent periodic duty with start
This is a sequence of identical duty cycles, each consisting load for a period, an operation at constant
load period, followed by a stationary and de-energized period. This cycle has a great impact on
temperature rise.