Overload Relays General data 1) The SIRIUS 3RU11 thermal overload relays use a bimetal contactor and therefore do not require a control supply voltage.
6 Siemens · 2009 Features Benefits 3RU11 3RB20/3RB21 3RB22/3RB23 3RU11 3RB20/3RB21 3RB22/3RB23 Other features Internal power supply • Eliminates the need for configuration and connec- ting an additional control circuit --1) ✔ -- Variable adjustment of the trip classes (The required trip class can be adjusted by means of a rotary switch depending on the current start-up condition.) • Reduces the number of variants • Minimizes the configuring outlay and costs • Minimizes storage overhead, storage costs, and tied-up capital -- ✔ (only 3RB21) ✔ Overload warning • Indicates imminent tripping of the relay directly on the device due to overload, phase unbalance or phase failure • Allows the imminent tripping of the relay to be signaled • Allows measures to be taken in time in the event of continuous inverse-time delayed overloads • Eliminates the need for an additional device • Saves space in the control cabinet • Reduces wiring outlay and costs -- -- ✔ Analog output • Allows the output of an analog output signal for ac- tuating moving-coil instruments, feeding program- mable logic controllers or transfer to bus systems • Eliminates the need for an additional measuring transducer and signal converter • Saves space in the control cabinet • Reduces wiring outlay and costs -- -- ✔