General Device Description; Figure 8-5: Current And Torque Curves For A Soft Starter - Siemens sirius System Manual

3RW3 semiconductor motor control unit

8.2.2 General device description

Normal switching
duty
8-10
I
I
starting f
100% U
I
starting
0.7 x
70% U
I
starting f
0.5 x
50% U

Figure 8-5: Current and torque curves for a soft starter

The SIRIUS modular system offers a variety of alternatives for load feeders.
In addition to the star-delta starters (see Chapter 5, "3RA fuseless load feed-
ers"), the SIRIUS 3RW3 soft starters are also available.
The 3RW3 soft starters can be combined with the following SIRIUS devices:
• 3RT contactors
• 3RV circuit breakers
• 3RU thermal overload relays
• 3RB10 electronic overload relays
They are all mounted and connected up in the same way.
Please note the relevant guidelines in Section 8.3.2.
Functions of the load feeder
Normal switching duty of a circuit can, according to the definitions of isola-
tion and normal switching data in DIN VDE 0100 (see Section 8.1), be imple-
mented with a contactor or a soft starter alone.
M
grid
M
starting
grid
grid
M
starting
0.49 x
M
starting
0.25 x
n
n
syn
100% U
grid
70% U
grid
50% U
grid
n
n
syn
SIRIUS System Manual
GWA 4NEB 430 0999-02b