Siemens SIRIUS System Manual

3RT1/3RH1 contactors
SIRIUS System Manual
3-74
GWA 4NEB 430 0999-02b
Varistor
Figure 3-56: Circuit with a varistor (AC/DC operation)
This is what happens when a coil is disconnected that is connected to a
varistor (voltage-dependent resistor):
Voltage peaks still occur. They are cut off at approximately 400 V and have a
shorter overall duration (approximately 50 microseconds).
(Note: The oscillogram is cut off, and the voltage is reduced to zero after
approximately 3 ms.)
A varistor is suitable for AC and DC operation.
The off-delay of the contactor is extended by approximately 2 to 5 ms.
RC element
Figure 3-57: Circuit with an RC element (AC/DC operation)
This is what happens when a coil is disconnected that is connected to an RC
element:
The amplitude and rate of rise of the switching overvoltage are reduced by
the capacitor. Showering arcs no longer occur. The voltage swings briefly to
400 V and then slowly drops down. This represents ideal damping.
Disadvantage: The component is larger and generally more expensive.
RC elements are suitable for AC and DC operation.
Only a minimal off-delay occurs (under 1 ms).
Circuit with a varistor
(
AC/DC o
p
eration
)
0
20
200
U
Sp
[V]
0
t [
µ
s]
U
Sp
Circuit with an RC element
(
AC/DC o
p
eration
)
0
5
200
U
Sp
[V]
t [ms]0
U
Sp

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