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

3.3

Protection of the soft starter against short circuits

SIRIUS 3RW44 manual
GWA 4NEB 535 2195-02 DS 01
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. To suit this purpose, special semiconductor fuses, e.g.
SITOR fuses from SIEMENS, must be used.
(Refer to Chapter 9.3 Technical data for the fuse assignment)
3/N/PE~ 50 Hz 400 V
L1
L2
L3
PE
G1
U1 V1 W1
V2
W2 U2
Fig. 3-7: Block diagram of branch with semiconductor fuses
Installation, connection and branch layout
Q1
F3
M1
U1 V1 W1
V2
W2 U2
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