Siemens 3RN2011, Manual, Page: 50 / 70

Functions
SIRIUS 3RN2 thermistor motor protection relay
50
Manual, 10/2016, A5E34244868002A/RS-AA/001
Auto RESET
Once the sensor circuit has cooled down, the 3RN2000 and 3RN2010 thermistor motor
protection relays are automatically reset. You can activate this function on the units with
remote RESET (3RN2012, 3RN2013, and 3RN2023) with an external jumper across
terminals Y1 and Y2.
NOTICE
Motor startup
The motor must not start up automatically following tripping. You must not use "Automatic
RESET" mode in applications where there is a risk of personal injury or damage to property
if the motor restarts unexpectedly.
You will find a typical circuit diagram of separate motor starting irrespective of the selected
RESET behavior of a thermistor motor protection relay in the Circuit diagrams (Page 65)
chapter.
Manual RESET
With the blue TEST/RESET button, you can reset a tripped thermistor motor protection relay
again, assuming the sensor circuit for tripping has cooled down again (i.e. resistance of the
PTC sensor < 1500 Ω). For this purpose, the blue TEST/RESET button must be kept
pressed for between 0.5 and 2 s.
Remote RESET
You can reset a tripped unit again using the pushbutton with a floating NO contact at
terminals Y1 and Y2, provided the sensor circuit for tripping has cooled down again (i.e.
resistance of the PTC sensor < 1500 Ω).
Remote RESET possible by disconnecting the supply voltage
On the 3RN2011 thermistor motor protection relay, there is a further way of triggering a
remote RESET, namely by switching the supply voltage off and then on again. This requires
the sensor circuit for tripping to have cooled down (i.e. the resistance of the PTC sensor <
1500 Ω). To safely ensure a complete device reset, you must switch off the supply voltage
for at least 500 ms.
All other versions with manual RESET have a non-volatile error memory. This error memory
permits a RESET after a trip only by operation of the pushbutton on the device or a
connected NO contact, at terminals Y1/Y2.