SIRIUS 3RU2/3RB3 overload relays 
  5.8 Operation 
SIRIUS Innovations 
System Manual, 01/2011, A8E56203870002-03 
521 
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. If these components are OK, the device is 
tripped in accordance with the table below. In the event of an error, the device is not tripped. 
 
Tripping class  Required loading with 
the rated current prior to 
pressing the TEST button 
Tripping within 
CLASS 5  3 min  30 s 
CLASS 10  5 min  1 min 
CLASS 20  10 mins  2 mins 
CLASS 30  15 mins  3 min 
 
 
 
Note 
The TEST button must be held down throughout the test. In this case the motor current must 
be > 80% of the current setting I
e
 and equal to at least the value of the lower current setting. 
 
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. This simulation 
process opens the NC contact and closes the NO contact, thereby checking that the auxiliary 
circuit has been wired correctly. The relay is reset after a test trip by pressing the RESET 
button. 
The user test has been completed successfully if: 
●  The device trips within the maximum permissible time and 
●  Contact 95-96 is open (test for welding)