Actuating Systems; Short-Circuit Protection Of The Sirius Contactors; Table 3-8: Actuating Systems - Siemens sirius System Manual

3RT1/3RH1 contactors
Auxiliary contacts and
built-on accessories

3.2.1 Actuating systems

3.2.2 Short-circuit protection of the SIRIUS contactors

Coordination types
Coordination type 1
3-12
• A uniform and diverse range of auxiliary switches and accessories that
can be quickly upgraded and replaced is available for 3RT1 contactors up
to 45 kW for various applications.
• The 3RH auxiliary contactors can be extended to form variants with a
maximum of 8 poles using attachable 2 or 4-pole auxiliary switch blocks.
• Wiring kits with and without mechanical interlocking are available for put-
ting together 3RA contactor combinations for reversing and for star-delta
starting.
The accessories are described in detail in Section 3.4, "Accessories".
AC coil:
DC coil:

Table 3-8: Actuating systems

Section 3.7, "Technical specifications", has information on short-circuit pro-
tection. Fuses and circuit breakers can be used as short-circuit protective
devices for the contactors.
The test criteria that apply in this case are stipulated by EN 60 947-4-1
(VDE 0660 Part 102).
Two types of assignment are defined in the standards that correspond to
two different levels of damage.
The following applies to both types of assignment:
In the event of a short-circuit, the short-circuit protective device used must
be able to disconnect the overcurrent that occurs both safely and success-
fully. Persons or other parts of the system must not be put at risk.
The load feeder (e.g. motor starter) can be inoperable after each short-circuit
disconnection. Damage to the contactor and the overload relay is permissi-
ble, but it is only possible to continue operation after defective devices have
been repaired or replaced.
• Ferromagnetic iron core (due to eddy current
losses)
• Adequate holding power
• Automatic reduction from high closing power to
low holding power
• Short switching times
• Solid parts are permissible
• Larger unit volumes (to achieve a tensile force
comparable to that of an AC coil)
• High holding power
• Closing power = holding power
• Longer switching times
SIRIUS System Manual
GWA 4NEB 430 0999-02b