Siemens SIRIUS System Manual

3RU11, 3RB10, and 3RB12 overload relays
SIRIUS System Manual
GWA 4NEB 430 0999-02b
4-13
4.2.3 Operation
Short-circuit protection
For short-circuit protection of starter combinations consisting of a contactor
and an overload relay, fuses or 3RV13 circuit breakers are required for
starter combinations.
Use with external cur-
rent transformers
If external current transformers are to be used to operate the 3RB12, the
following things should be taken into consideration. The 3RB12 with the cur-
rent setting range from 1.25 to 6.3 A must be selected.
The secondary current of the 1 A or 5 A current transformer becomes the
primary current of the 3RB12. In the case of 5 A current transformers, the
3RB12 can be set from 1.25 to 5 A (i.e. from 1/4 of to 1 times the trans-
former's rated current). In the case of 1 A current transformers, a signal
> 1.25 A must be generated by looping the line. If the line is looped five
times, a 5 A signal is generated for the 3RB12.
Environmental conditi-
ons
3RU11
The 3RU11 overload relays can be used without restrictions at ambient tem-
peratures of up to 60 °C. This is the result of new bimetals and continuous
temperature compensation (up to 70 °C with derating).
3RB10
A special coating on the PCB and the electronic components ensures reli-
able operation even in corrosive and tropical environmental conditions.
Auxiliary contact ele-
ments
The 3RU11 and 3RB10 overload relays are equipped with a normally closed
contact for switching off the contactor and a normally open contact for the
tripped signal.
The switching contacts have a high switching capacity so that they can
switch contactor coils directly. The overload relays are therefore suitable for
use with a PLC (17 V, 5 mA).
Coil and auxiliary
switch repetition termi-
nal
Frame size S00
In the case of direct mounting onto contactors, the auxiliary switch and coil
repeat terminals (A2) are passed through the 3RU1116 and 3RB1016 over-
load relays. This makes wiring much simpler.
Frame sizes S0 - S3
The contactors of these frame sizes are equipped with 4 coil connections. It
is therefore not necessary to pass through the auxiliary switch and coil ter-
minals (A2) of the contactor.

Siemens SIRIUS Specifications

General

Product brand name	Siemens
Series	SIRIUS
Coil Voltage	24V DC, 110V AC, 230V AC
Switching Capacity	Up to 10A
Mounting Type	DIN rail
Product designation	SIRIUS
Contact Material	Silver alloy
Contact Rating	Varies depending on the specific SIRIUS relay model (e.g., 6 A at 250 V AC, 10 A at 250 V AC)
Switching Voltage	Varies depending on the specific SIRIUS relay model (e.g., 250 V AC, 400 V AC)
Mechanical Life	Up to 10 million operations
Electrical Life	Up to 100, 000 operations
Operating Temperature	-25°C to +55°C
Protection Class	IP20
Size of relay base	Varies depending on the specific SIRIUS relay model