Protection Of The Soft Starter Against Short Circuits - Siemens SIRIUS 3RW44 System Manual

3.3

Protection of the Soft Starter against Short Circuits

(Utilization class 2)
SIRIUS 3RW44 System Manual
GWA 4NEB 535 2195-02 DS 04
The soft starter has integrated thyristor protection against overloading. In the
event of a short circuit, e.g. due to a defect in the windings of the motor or a
short-circuit via the motor supply cables, this internal thyristor protection function
is not sufficient. Special semiconductor fuses, e.g. SITOR fuses from SIEMENS,
must be used for this purpose.
(Refer to Chapter 10.3 "Technical Data" for the fuse assignment)
3/N/PE~ 50 Hz 400 V
L1
L2
L3
PE
U1 V1 W1
V2
W2 U2
Figure 3-7:Block diagram of branch with semiconductor fuses
Installation, Connection and Branch Layout
Q1
F3
Q11
G1
M1
U1 V1 W1
V2
W2 U2
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