Soft Starting With Voltage Ramp - Siemens SIRIUS 3RW55 Manual

7.2.3

Soft starting with voltage ramp

Operating principle
A voltage ramp is used to implement soft starting. The 3RW55 soft starter increases the
motor voltage from a parameterizable starting voltage to the line voltage within a definable
ramp-up time.
Application
● Conveyor belts
● Systems in which a startup of the drive without interfering jerky movements is required.
Diagrams
①
②
U
rated
U
S
t
1
t
2
SIRIUS 3RW55 soft starter
Manual, 08/2018, A5E35630887002A/RS-AB/002
Voltage ramp with short ramp-up time t
Voltage ramp with long ramp-up time t
Line voltage
Parameterizable starting voltage
Short ramp-up time
Long ramp-up time
1
2
Functions
7.2 Start-up
83