Siemens SIRIUS 3RW55 - A.1.3 Feeder Assembly, Type of Coordination 2

Example circuits
A.1 Main circuit connection
SIRIUS 3RW55 soft starter
Manual, 08/2018, A5E35630887002A/RS-AB/002
203
A.1.3
Feeder assembly, type of coordination 2
Feeder assembly, type of coordination 2
In order to achieve type of coordination 2, you must provide protection for all thyristors
against short circuits by means of special semiconductor fuses (e.g. SITOR fuses from
Siemens). A short circuit can occur, for instance, as a result of a defect in the motor windings
or in the motor's power supply cable.
Q1
Motor starter protector
F3
aR partial-range fuse for protection of semiconductors (e.g. SITOR 3NE3/4 or 3NC3)
F3*
gR full-range fuse for protection of semiconductors (e.g. SITOR 3NE1)
Q11
Soft starter
M1
Motor
PE
Protective conductor