Overload Relays 3RB2 Solid-State Overload Relays 3RB22, 3RB23 for high-feature applications "Increased safety" type of protection EEx e acc. to ATEX di- rective 94/9/EC Connection methods Main circuit (current measuring module) The 3RB22 (monostable) solid-state overload relays are suitable for the overload protection of explosion-proof motors with "increa- sed safety" type of protection EEx e; see Catalog LV 1, Chapter 20 "Appendix" --> "Standards and Ap- provals" --> "Type Overview of Approved Devices for Explosion- Protected Areas (ATEX Explosion Protection)". For sizes S00/S0, S2/S3 and S6, the main circuit can also be con- nected by the straight-through transformer method.
In this case, the cables of the main circuit are routed directly through the feed- through openings of the relay to the contactor terminals. Design For sizes S6 and S10/S12, the main circuit can be connected with the help of rails. In conjunction with the corresponding box termi- nals, screw connection is also possible. Device concept Auxiliary circuit (evaluation module) The 3RB22/3RB23 solid-state overload relays are based on a mo- dular device concept. Each device always comprises an evalua- tion module, which is independent of the motor current, and a cur- rent measuring module, which is dependent on the motor current.
The two modules are electrically interconnected by a connection cable through the system interface. Connection of the auxiliary circuit (removable joint block) is pos- sible with either screw or spring-type terminal connection system (special versions). For more information on the connection options see "Technical specifications" and Catalog LV 1, "Selection and ordering data" . The basic functionality of the evaluation module can be optionally expanded with corresponding function expansion modules. The function expansion modules are integrated in the evaluation mo- dule for this purpose through a simple plug-in connection.
Overload relays in contactor assemblies for wye-delta starting When overload relays are used in combination with contactor assemblies for wye-delta starting it must be noted that only 0.58 times the motor current flows through the line contactor. An overload relay mounted onto the line contactor must be set to 0.58 times the motor current. Mounting options Current measuring modules When 3RB22/3RB23 solid-state overload relays are used in com- bination with contactor assemblies for wye-delta starting, the function expansion modules for internal ground-fault detection must not be used. The current measuring modules size S00/S0 and S2/S3 are desi- gned for stand-alone installation.
By contrast, the current measu- ring modules size S6 and S10/S12 are suitable for stand-alone in- stallation and mounting onto contactors. Operation with frequency converter Evaluation modules The evaluation modules can be mounted either on the current measuring module (only sizes S00/S0 and S2/S3) or separately. The 3RB22/3RB23 solid-state overload relays are suitable for fre- quencies of 50/60 Hz and the associated harmonics. This permits the 3RB22/3RB23 overload relays to be used on the input side of the frequency converter. For more information on the mounting options see "Technical spe- cifications" and Catalog LV 1, "Selection and ordering data" .
If motor protection is required on the outgoing side of the fre- quency converter, Siemens recommends the 3RN thermistor mo- tor protection devices or the 3RU11 thermal overload relays for this purpose. 30 Siemens · 2009