Functions
SIRIUS 3RN2 thermistor motor protection relay
48
Manual, 10/2016, A5E34244868002A/RS-AA/001
3RN2010, 3RN2011, 3RN2012, and 3RN2013 standard units
The standard units are equipped with two LEDs (READY and TRIPPED) for an operating
and tripped display and are available with either 1 NO + 1 NC contacts (3RN2010, overall
width 17.5 mm) or with 2 CO contacts. Depending on the version, they are available with
Auto RESET (3RN2010), Manual/Remote RESET (3RN2011 – Remote RESET only by
switching the unit off and on again, as no Y1/Y2 terminals available) or Manual/Auto and
Remote RESET (3RN2012 and 3RN2013). Remote RESET can be achieved by connecting
an external pushbutton with a normally-open function to terminals Y1 and Y2
(3RN2012/3RN2013) or by switching the unit off and on again (3RN2011). If terminals Y1
and Y2 are jumpered, the unit is automatically reset once the thermistors have cooled down
(Auto RESET). The 3RN2012 and 3RN2013 units are non-volatile. This means a previous
trip remains stored in the event of a control supply voltage failure. The thermistor motor
protection relay remains in the safe state with an opened output relay until it is intentionally
reset by pressing the TEST/RESET button of the unit or an external pushbutton.
When using the 3RN2012-.BW31 devices with bistable relays, the switching status of the
output relays does not change in the event of a loss of supply voltage or a system stop, but
the connected motor is no longer monitored. Separate supply voltage monitoring is therefore
recommended.
3RN2023 "Warning and tripping" thermistor motor protection relays
You can connect two sensor circuits to one 3RN2023 thermistor motor protection relay that
act on two separate output relays with 1 NO contact for warning and 1 CO contact for
tripping. Thermistors with different rated response temperatures TNF are used to implement
the "Warning" and "Tripping" functions. When sensor circuit 2 for "Warning" responds, a
yellow LED is lit and when the "Tripping" circuit responds, a red LED is lit. The sensor
circuits have different reset response and operating behavior: "Warning" thermistor sensor
circuit 2, (terminals 2T1, T2) works only with Auto RESET and according to the open-circuit
principle (output relay K2, NO contact). "Tripping" thermistor sensor circuit 1, (terminals 1T1,
T2) can be changed from Manual RESET to Auto RESET by jumpering terminals Y1 and Y2.
Remote RESET is implemented by connecting an external pushbutton with a normally-open
function to these terminals.
Note
Devices with ATEX approval
Note that not all devices have ATEX approval.
All devices with article numbers 3RN2011, 3RN2012-.B.30, 3RN2013, and 3RN2023 have
ATEX approval.
All devices with article numbers 3RN2000, 3RN2010 and 3RN2012-..31 (bistable type) do
NOT have ATEX approval.
In this regard, please also note the information in theSafety and commissioning instructions
for hazardous areas (Page 15) chapter.