SIRIUS 3RU2/3RB3 overload relays   
5.6 Mounting 
  SIRIUS Innovations 
510  System Manual, 01/2011, A8E56203870002-03 
Table 5- 15  Mounting the 3RU21 overload relay with a spring-loaded connection system 
Step  Operating instruction  Figure 
1  Insert the contacts (a) into the central opening 
of the main conductor terminals on the 
contactor (see below, a), with the contacts 
flush to the right. Make sure that the guide 
tabs are inserted into the designated slots on 
the contactor. 
The overload relay will sit flush with the 
contactor on the left- and right-hand sides. 
D
 
 
The table below shows the openings of the main conductor terminals on the contactor into 
which the overload relay contacts have to be inserted. 
 
Main conductor terminals on the contactor (a) 
(S00): 
Main conductor terminals on the contactor (a) 
(S0): 
 
 
 
 
 
Note 
Ring cable lug connection system 
The procedure for mounting the overload relays with ring cable lug connection system is 
similar to that for mounting with screw-type connection system.