SIRIUS overload relays with screw-type, spring-loaded or ring cable lug connections reliably protect loads as well as other switching and protective devices in the respective load feeder against overload, phase asymmetry and phase failure. Thanks to ATEX certification, they can be used in many different applications and are even suitable for protecting motors designed for use in explosive environments. The overload relays can easily be used with the contactors of the SIRIUS module kit.
For demanding applications, the modular variants of the 3RB22, 3RB23 or 3RB24 electronic overload relays even offer full motor protection using connected thermistors to sense the motor temperature, as well as comprehensive display and signaling functions, and a communication link using IO-Link.
Optimized, standard accessories are available for 3RU2 and 3RB3. This helps to reduce costs for ordering and maintaining stocks.
SIRIUS 3RB24 Overload relays
SIRIUS 3RB24 overload relays for IO-Link protect motors against overload, can start motors, and can switch motors under normal operation conditions.
There are two versions of overload relays: thermal overload relays using bimetals and electronic overload relays using current transformers.
SIRIUS 3RU thermal overload relays
In the main circuit, the SIRIUS 3RU thermal overload relays are responsible for current-dependent overload protection of electrical loads (e.g. motors). The 3RU2 overload relays are available with spring-loaded, screw-type and ring cable lug connections - for a particularly flexible and cost-effective implementation.
SIRIUS 3RB electronic overload relays
The SIRIUS 3RB electronic overload relays ensure real commercial added value: in the main circuit, the 3RB30 electronic overload relays for standard applications are responsible for current-dependent overload protection of electrical loads (e.g. motors). Due to the wide current setting ranges and various tripping characteristics, complete series of motors are covered with just a few types. The 3RB31 version offers enhanced functions, such as an integrated, electrical remote reset or ground fault detection to name but a few.
SIRIUS 3RB24 electronic overload relay for IO link
With the communication-capable SIRIUS 3RB24 electronic overload relay for IO link you can easily connect your load feeder to a higher-level control and therefore integrate it into your automation environment. As the electronic overload relay supports the transmission of analog process variables such as currents, system processes can be optimized, e.g. through load monitoring.
Moreover, you will benefit from an increased system availability and simpler system documentation – thanks to integrated diagnostics functions and readable parameter assignment. In combination with contactors, the overload relay can also be used a as direct-on-line and reversing starter. Thanks to the IO-Link connection, all connected contactors can be functionally switched on or off, even on-site, using a hand-held device.
Overload relays for efficient energy management
Energy-efficient SIRIUS industrial controls help to minimize consumption and systematically increase efficiency. With our overload relays, you benefit from comprehensive advantages in terms of energy efficient industrial controls:
Advantages at a glance
Switch-off during the idles state (e.g. pump idling)
Reactive-power compensation with power factor monitoring
Shedding of defined loads when current limit exceeded
Requirement-based, temperature-controlled heating and ventilation control in the process and in the cabinet
More information about the topic of energy efficiency and PROFIenergy at Siemens:
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Overload Relays Catalogs, Diagrams...
SIRIUS 3RR Current Monitoring Relays
SIRIUS 3RB24 Solid-State Overload Relays (IO link)
Integrated motor protection for high-feature