3RW3 semiconductor motor control unit
SIRIUS System Manual
8-10
GWA 4NEB 430 0999-02b
Figure 8-5: Current and torque curves for a soft starter
8.2.2 General device description
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
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.
n
n
syn
M
starting
M
M
starting
M
starting
100% U
grid
70% U
grid
50% U
grid
0.49 x
0.25 x
n
n
syn
I
starting
f
I
I
starting
0.7 x
I
starting
f
0.5 x
100% U
grid
70% U
grid
50% U
grid
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