
B-65292EN/03 APPENDIX A.DEFINITION OF RATING
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A DEFINITION OF RATING
The IEC34 standard uses symbols S1, S2, and S3 according to the
types of motor rating. Each type of rating is described below:
Continuous rating (S1)
The motor can continuously be run at the indicated output.
Example)
15kW S1, 15kW S1 Cont.
Meaning)
The motor can continuously be run at an output of 15 kW.
Short-time rating (S2)
The motor can be run at the indicated output within the indicated time
at room temperature.
Example)
18.5kW S2 30min.
Meaning)
The motor can be run at an output of 18.5 kW only for 30
minutes at room temperature.
Cyclic rating (S3)
The motor is run and stopped in a cycle of 10 minutes.
The ratio of the motor running time to 10 minutes is indicated as a
percentage (%).
Example)
22kW S3 25%, 25% ED 22kW
Meaning)
The motor can be run at an output of 22 kW when the total of the
motor running time is 2 minutes and 30 seconds in a 10-minute
cycle. (The motor is stopped for the rest of 7 minutes and 30
seconds.)
Remarks)
ED means the cyclic rating (S3).
ED is an abbreviation of Einschaltdauer (running time) in
German.