Mounting   
5.12 Disassembling the devices with device connectors from a standard mounting rail 
  SIRIUS 3RM1 motor starter 
104  Manual, 06/2016, A5E0345285095020A/RS-AE/005 
Press the device connector down. 
8  Pull the lower half of the device connector 
away from the standard mounting rail. 
9  Lift the device connector from the upper 
edge of the standard mounting rail.