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Siemens IC 10 · 2017
Relays
SIRIUS 3RN2 thermistor motor protection
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Overview
SIRIUS 3RN2 thermistor motor protection
Thermistor motor protection devices are used for direct
monitoring of the motor winding temperature. For this purpose,
the motors are equipped with temperature-dependent resistors
(PTC) that are directly installed in the motor winding and abruptly
change their resistance at their temperature limit.
Versions
SIRIUS 3RN2 thermistor motor protection relays are available in
the following versions:
•
3RN2000 compact evaluation unit
•
3RN2010 compact/standard evaluation unit
•
3RN2012-.BW31 bistable evaluation unit
•
3RN2011, 3RN2012-...30, 3RN2013 standard evaluation unit
with ATEX approval
•
3RN2023 evaluation unit with ATEX approval and 2 sensor
circuits for warning and disconnection
The 3RN2 thermistor motor protection relays are suitable for use
in any climate and are finger-safe according to IEC 60529.
They comply with
•
IEC 60947-8. Low-voltage switchgear and controlgear –
Part 8: "Control units for built-in thermal protection (PTC)
for rotating electrical machines"
•
IEC 61000-6-2, IEC 61000-6-4. "Electromagnetic compatibility
for industrial-process measurement and control equipment"
The 3RN2 thermistor motor protection relays with ATEX approval
fulfill SIL1 in compliance with EN 50495.
The terminals of the auxiliary contacts are designated in
accordance with EN 60947-1.
3RN2 evaluation units are suitable for snap-on mounting onto
TH 35 standard mounting rails according to IEC 60715 or for
screw fixing using an adapter (accessory).
Article No. scheme
Note:
The Article No. scheme is presented here merely for information
purposes and 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.
More information
Home page,
see www.siemens.com/relays
Industry Mall,
see www.siemens.com/product?3RN2
Conversion tool, e.g. from 3RN1 to 3RN2,
see
Product versions
Article number
Thermistor motor protection relay with PTC sensor, type A
3RN20
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Number and type
of sensor circuits
1 sensor circuit, supply voltage = root voltage
0
1 sensor circuit
1
2 sensor circuits for warning and disconnection
2
RESET
Auto RESET
0
Manual RESET, with open-circuit and short-circuit detection
1
Manual/Auto/Remote RESET, non-volatile,
with open-circuit and short-circuit detection
2
Manual/Auto/Remote RESET, non-volatile,
with open-circuit and short-circuit detection,
with protective separation
3
Connection method
Screw terminals
1
Spring-type terminal
2
Auxiliary switches
1 CO
A
2 CO
B
1 NO + 1 NC
C
1 NO + 1 CO
D
2 CO, hard gold-plated
G
Rated control supply voltage
24 V AC/DC
A
3
24 ... 240 V AC/DC
W
3
Response to failure
Monostable
0
Bistable
1
Example
3RN20
0
0
–
1
A
A
3
0
© Siemens AG 2016