Siemens SIRIUS 3RW52 Equipment Manual page 142

Functions
8.6 Soft Torque
Speed curve
n
e
Operating principle of Soft torque during stopping
The Soft torque function enables the motor to coast down smoothly at an almost constant
rate of deceleration. Ensuring that the motor coasts down smoothly is particularly useful for
stopping pumps in order to prevent water hammers in the connected piping. The Soft torque
function for stopping can only be activated when a stopping time of more than 3 seconds is
set.
Speed curve
n
e
142
Rated operating speed of the motor
Motor speed without Soft torque
Motor speed with Soft torque
Rated operating speed of the motor
Motor speed with Soft torque
Motor speed without Soft torque
Equipment Manual, 04/2020, A5E35630451002A/RS-AE/005
SIRIUS 3RW52 Soft Starter