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Siemens IC 10 · 2017
Solid-State Switching Devices for Resistive/Inductive Loads
General data
6
Article No. scheme
Note:
The Article No. scheme shows an overview of product versions
for better understanding of the logic behind the article numbers.
For your orders please use the article numbers quoted in the
selection and ordering data.
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Benefits
Features
• Considerable space savings thanks to a width of only 22.5 mm
• Variety of connection methods: Screw terminal, spring-type
connection or ring terminal lug, there is no problem – they are
all finger-safe
• Flexible for all applications with function modules for retrofitting
• Possibility of fuseless short-circuit proof design
Benefits
• Saves time and costs with fast mounting and commissioning,
short start up times and easy wiring
• Extremely long life, low maintenance, rugged and reliable
• Space-saving and safe thanks to side-by-side mounting up to
an ambient temperature of +60 °C
• Modular design: Standardized function modules and heat
sinks can be used in conjunction with solid-state relays to
satisfy individual requirements
• Safety due to lifelong, vibration-resistant and shock-resistant
spring-type terminal connection method even under tough
conditions
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Application
Applications
Example: Plastics processing industry
Thanks to their high switching endurance SIRIUS 3RF2 solid-
state switching devices are ideal for controlling electrical heat.
This is because the more precise the temperature regulation
process has to be, the higher the switching frequency. The
accurate regulation of electrical heat is used for example in
many processes in the plastics processing industry:
•Band heaters heat the extrudate to the correct temperature in
plastic extruders
•Heat emitters heat plastic blanks to the correct temperature
•Heat drums dry plastic granules
•Heating channels keep molds at the correct temperature in
order to manufacture different plastic parts without defects
The powerful SIRIUS 3RF2 solid-state relays and contactors can
be used for the simultaneous control of several heating loads. By
using a load monitoring module the individual partial loads can
easily be monitored, and in the event of a failure a signal is
generated to be sent to the controller.
Product versions
Article number
Solid-state switching devices
for resistive/inductive loads
Solid-state relays
3RF20
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1-phase, 45-mm width
3RF21
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1-phase, 22.5-mm width
3RF22
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3-phase, 45-mm width
Solid-state contactors
3RF23
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Single-phase
3RF24
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Three-phase
Type current
e.g. 20 = 20 A
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Connection type
Screw terminals
1
Spring-type terminals
2
Ring terminal lug connection
3
Switching function
Zero-point switching
A
Instantaneous switching
B
Zero-point switching
C
Low Noise
Zero-point switching
D
Short-circuit-proof with B MCB
Single-phase or number of
controlled phases
Single-phase
A
2-phase
B
Three-phase
C
Reversing contactor
D
Rated control supply voltage
U
s
24 V DC
0
24 V AC/DC
1
110 ... 230 V AC
2
110 V AC
3
4 ... 30 V DC
4
230 V AC
5
Rated operational voltage
U
e
24 ... 230 V AC
2
48 ... 460 V AC
4
48 ... 600 V AC
5
48 ... 600 V AC
6
Blocking voltage 1600 V
Example
3RF21
2
0
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1
A
A
0
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© Siemens AG 2016