Siemens SIMATIC ET 200pro - 8.3 Electronic starters sDSSte; sDSte; sRSSte; sRSte

SIMATIC – ET 200pro motor starter
GWA 4NEB 950 5661-02 DS 04
8-17
8.3 Electronic starters sDSSte / sDSte / sRSSte / sRSte
The electrical properties of the direct soft starter DSSe are comparable with
those of the 2-phase SIRIUS soft starter.
The following variants of type 1 are available:
• 2 A without bridge
• 12 A with bridge
8.3.1 Basic physical principles
Start-up current
Three-phase current induction motors have a high switch-on current I
(start-up)
.
Depending on the motor version, this can lie between 3 and 15 times the rated
operating current. 7 to 8 times the motor rated current can be assumed as a
typical value.
Figure 8-8: Typical current and torque characteristics of a 3-phase induction motor
I
start-up
I
0 (idling)
I
I
rated
n
rated
n
syn
n
M
n
M
start-up
M
pull-up
M
motor
M
tilt
M
motor
M
rated
n
rated
n
syn
M
accel
M
load
M
load