SIEMENS
SIEMENS 3RU21261EB0 Overload Relay 2.8-4A Trip Class 10 690V AC
Thermal overload relay protects three-phase motors with 2.8–4 A trip range, Trip Class 10 and 690 V AC rating
- Thermal protection for 2.8–4 A motor circuits
- Trip Class 10 response limits overheating damage
- 690 V AC rating suits industrial supplies
- Auto and manual reset restores operation fast
- Direct contactor mounting simplifies panel wiring
Overload Relay 2.8-4 A Trip Class 10
The SIEMENS 3RU21261EB0 is a thermal overload relay designed for three-phase motor protection in industrial control panels. It mounts directly to a compatible SIRIUS contactor using screw terminals for secure wiring. The adjustable current range spans 2.8 A to 4 A, covering a specific band of motor full-load currents. It suits maintenance teams and panel builders who need IEC-style protection for S0 frame contactors.
1NO/1NC Auxiliary Contacts Included
The built-in auxiliary block provides one normally-open and one normally-closed contact for signalling or interlocking circuits. Thermal elements are supplied with the unit, so no separate heater packs are required during installation. Auto and manual reset modes let operators choose between automatic restart and supervised reset after a trip event. This integration reduces component count and wiring time inside the starter assembly.
690 V AC Maximum Voltage Rating
The relay is rated for a maximum of 690 V AC, limiting its use to systems operating at or below this level. Trip Class 10 defines a fixed tripping characteristic that may not suit motors with long acceleration times or high inertia loads. Direct contactor mounting restricts application to SIRIUS S0 frame devices, so other frame sizes or brands require a different relay. Phase-loss sensitivity depends on the thermal mechanism inherent to the design.
Highlights
- Thermal protection for 2.8–4 A motor circuits
- Trip Class 10 response limits overheating damage
- 690 V AC rating suits industrial supplies
- Auto and manual reset restores operation fast
- Direct contactor mounting simplifies panel wiring
Specifications
| Brand | SIEMENS |
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Questions about this item
Will the 1NO/1NC auxiliary contact on this 3RU21261EB0 relay need periodic replacement?
The auxiliary contact is built into the overload relay and has no separate replacement schedule; it is replaced only if the entire relay is changed.
What limits continuous operation of this relay at its 4 A maximum setting?
The thermal trip mechanism calibrated for Trip Class 10 opens the circuit when sustained current exceeds the 2.8–4 A range.
How much heat does the relay produce when mounted on a contactor and running at 4 A all day?
Heat comes from the three internal thermal units carrying load current; the relay is designed to dissipate it through direct contactor mounting.
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