Siemens SIRIUS 3RW30 Manual page 25

The diagrams below show the starting current and torque characteristics for a three-phase
induction motor in combination with a soft starter:
Figure 3-1
Figure 3-2
Soft start /soft stop
This means that, since the motor voltage is controlled by the electronic soft starter during the
startup process, the consumed starting current and the starting torque generated in the
motor are also controlled.
The same principle is applied during the stop process. This ensures that the torque
generated in the motor is gradually reduced, so that the application can stop smoothly (the
soft stop function is only supported by the 3RW40).
SIRIUS 3RW30 / 3RW40
Manual, 10/2018, NEB535199502000/RS-AB/005
3.2 Functional principle of the SIRIUS 3RW30 and 3RW40 soft starters
Reduced current characteristic of a three-phase induction motor during starting with a
SIRIUS 3RW30 or 3RW40 soft starter
Reduced torque characteristic of a three-phase induction motor during starting with a
SIRIUS 3RW30 or 3RW40 soft starter
Product description
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