Siemens SINAMICS S120 Configuration Manual page 65

Load duty cycles with varying on period
As well as continuous duty (S1), standard intermittent duty types (S3) are also defined for
load duty cycles with varying on periods. This involves operation that comprises a sequence
of similar load cycles, each of which comprises a time with constant load and an off period.
Figure 5-6
Figure 5-7
Fixed variables are usually used for the relative on period:
• S3 – 60%
• S3 – 40%
• S3 – 25%
The corresponding motor characteristics are provided for these specifications. The load
torque must lie below the corresponding thermal limiting characteristic curve of the motor.
An overload must be taken into consideration for load duty cycles with varying on periods.
Synchronous Motors 1FK7
Configuration Manual, (PFK7S), Edition 12.2006, 6SN1197-0AD16-0BP1
S1 duty (continuous operation)
S3 duty (intermittent operation without influencing starting)
Configuration
5.3 Dimensioning
65