Siemens 3RW44 Manual page 15

2.1 Basic physical principles of the three-phase asynchronous motor and operating principle of the soft starter
Example
SIEMENS 1LG4253AA motor (55 kW)
Rated data at 400 V
P :
e
I :
e
I
direct starting
M :
e
n :
e
M
direct starting
Set starting voltage:
=> I
=> M
The diagrams below show the starting current and torque characteristics for a three-phase
asynchronous motor in combination with a soft starter:
Figure 2-3
3RW44 soft starters
Manual, 03/2017, NEB535219502000/RS-AB/008
:
:
½ of direct-on-line starting switch-on current (approx. 350 A)
starting
¼ of direct-on-line starting torque (approx. 175 Nm)
starting
Reduced current characteristic of a three-phase asynchronous motor during startup with
a SIRIUS 3RW44 soft starter
55 kW
100 A
approx. 700 A
355 Nm
Example:
1480 rpm
approx. 700 Nm
50 % (½ of line voltage)
Introduction
15