Siemens SIRIUS System Manual

3RT1/3RH1 contactors
SIRIUS System Manual
GWA 4NEB 430 0999-02b
3-9
3.1.4 Explanation of terms
Safety extra-low volt-
age
Safety extra-low voltage (SELV) allows circuits with a rated voltage of up to
50 VAC or 120 VDC to be operated ungrounded. The higher voltage is safely
isolated from the SELV circuits.
Safety extra-low voltage helps protect people.
Functional
extra-low voltage
Functional extra-low voltage (FELV) allows circuits with a rated voltage of up
to 50 VAC or 120 VDC can be operated. It does not, however, meet the
requirements of safety extra-low voltage and is therefore subject to additio-
nal conditions. FELV is implemented using a ground terminal.
Functional extra-low voltage helps protect devices (e.g. programmable con-
trollers).
PELV
PELV (protective extra-low voltage) has the same requirements as safety
extra-low voltage, except for the fact that the circuit and/or exposed conduc-
tive part is/are grounded (so it is basically grounded SELV).

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