Additional Functions - Siemens SIRIUS 3RT Series System Manual

SIRIUS 3RU2/3RB3 overload relays
5.4 Functions
5.4.6

Additional functions

RESET function
There are various ways to reset the device following an overload release.
Table 5- 7
Overload relay
3RU21
3RB30
3RB31
The relay cannot be reset until after the recovery time has elapsed.
Stop function (3RU21 only)
Pressing the STOP button on the 3RU21 thermal overload relay opens the NC contact,
thereby disconnecting the downstream contactor and thus the load. The load is switched
back on via the contactor when the STOP button is released. In the case of maintained-
contact operation in the auxiliary circuit, the load is switched back on via the contactor when
the red STOP button is released.
Test function for the 3RU21 thermal overload relay
The TEST slide can be used to check whether the operational 3RU21 thermal overload relay
is working properly. The tripping of the relay can be simulated by moving the slide. This
simulation process opens the NC contact (95-96) and closes the NO contact (97-98), thereby
checking that the auxiliary circuit has been wired to the overload relay correctly.
Test function for the 3RB30/3RB31 solid-state overload relay
The correct function of the relay when ready for operation can be checked by pressing the
TEST button with the motor current flowing (device/electronics test). Current sensing, the
motor model, and the tripping unit are tested.
The switch position indicator slide can be used to test the auxiliary contacts and the control
current wiring. The tripping of the relay can be simulated by moving the slide, thereby
providing a means of checking that the auxiliary circuit has been wired correctly.
Reference
More information ...
About the RESET function
About the test function
502
RESET options for for overload relays
Auto RESET Manual
RESET
✓
✓
✓
Mech. remote RESET
(accessory)
Release slide
✓ ✓
✓ ✓
✓ ✓
Can be found in...
The chapter titled RESET after release
(Page 517)
The chapter titled TEST function (Page 520)
System Manual, 01/2011, A8E56203870002-03
Elect. remote
RESET
Cable release
✓ ✓
(accessory)
✓ -
✓ ✓
(built-in)
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