Overview

For an introduction to the 3RU and 3RB overload relays, together with the general data on the various series and the assignments of the overload relays to the contactors, see the following PDF.

Connection methods

3RU2 thermal overload relays

• Sizes S00 and S0:
  • Main and auxiliary circuit: optionally screw or spring-type terminals
• Sizes S2 and S3:
  • Main circuit: screw terminals with box terminal
  • Auxiliary circuit: optionally screw terminals or spring-type terminals

3RB3 electronic overload relays

• Sizes S00 and S0:
  • Main and auxiliary circuit: optionally screw terminals or spring-type terminals
• Sizes S2 and S3:
  • Main circuit: screw terminals with box terminal or as straight-through transformer
  • Auxiliary circuit: optionally screw terminals or spring-type terminals

3RB2 electronic overload relays

3RB20 and 3RB21 overload relays:

• Size S6:
  • Main circuit: with busbar connection or as straight-through transformer
  • Auxiliary circuit: optionally screw terminals or spring-type terminals
• Sizes S10/S12:
  • Main circuit: With busbar connection
  • Auxiliary circuit: optionally screw terminals or spring-type terminals

3RB22 to 3RB24 evaluation modules:

• Screw or spring-type terminals

3RB29 current measuring modules:

• Up to size S3: Straight-through transformers
• From size S6:
  • Main circuit: with busbar connection
  • Auxiliary circuit: optionally screw terminals or spring-type terminals