Siemens SIRIUS 3RW50 - Functions; 7.1 Soft starting

SIRIUS 3RW50 soft starter
Manual, 09/2019, A5E35628455002A/RS-AA/001
119
Functions
7
7.1 Soft starting
Operating principle
A voltage ramp is used to implement soft starting. The 3RW50 soft starter increases the
motor voltage from a parameterizable starting voltage to the line voltage within a definable
ramp up time.
Application
● Systems in which a startup of the drive without interfering jerky movements is required.
● E.g. pumps or small fans
Voltage characteristic
①
Voltage ramp with short ramp up time t
1
②
Voltage ramp with long ramp up time t
2
U
N
Line voltage
U
S
Parameterizable starting voltage
t
1
Short ramp up time
t
2
Long ramp up time