SIEMENS
SIEMENS 3RU21161GB0 Overload Relay 4.5-6.3 A
Thermal overload relay with 4.5–6.3 A range, 1NO/1NC auxiliary contacts and 690 V AC rating for direct contactor mounting
- Thermal protection for motors up to 6.3 A
- Adjustable trip range from 4.5 A to 6.3 A
- Trip Class 10 for standard motor starting
- Direct mounting on SIRIUS S00 contactors
- Screw terminals and auto or manual reset
SIEMENS 3RU21161GB0 Overload Relay 4.5-6.3 A
The SIEMENS 3RU21161GB0 is a thermal overload relay designed for motor protection in industrial control circuits. It suits electricians and maintenance engineers who need reliable overload monitoring for three-phase motors within a 4.5 A to 6.3 A current range. The unit mounts directly onto compatible SIRIUS contactors using screw terminals. Its Trip Class 10 response provides standard thermal protection for typical motor starting profiles.
Thermal protection limits and voltage rating
The relay operates with a minimum current setting of 4.5 A and a maximum of 6.3 A, protecting motors only within this defined window. It is rated for a maximum voltage of 690 V AC and requires three thermal elements for three-pole operation. The Trip Class 10 designation means it trips within a standard time under overload conditions. Applications needing higher current ranges, different trip classes or voltages beyond 690 V AC cannot use this device.
Direct contactor mounting and wiring notes
Installation is straightforward: the relay mounts directly to a matching SIRIUS S00 frame contactor and connects via screw terminals for both main and auxiliary circuits. The 1NO/1NC auxiliary contacts integrate into control circuits for signalling or interlocking. Misalignment with the contactor or incorrect thermal element selection are common issues. Ensure the contactor frame size matches S00 and that the motor full-load current falls within the 4.5 A to 6.3 A adjustment range before commissioning.
Highlights
- Thermal protection for motors up to 6.3 A
- Adjustable trip range from 4.5 A to 6.3 A
- Trip Class 10 for standard motor starting
- Direct mounting on SIRIUS S00 contactors
- Screw terminals and auto or manual reset
Specifications
| Brand | SIEMENS |
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Questions about this item
Should I choose the 4.5 A or 6.3 A setting for my motor?
Set the relay between 4.5 A and 6.3 A to match your motor's full-load current; the dial covers the whole range in one unit.
What does the 6.3 A maximum actually protect in a live circuit?
It trips when current exceeds the set value, protecting the motor windings from sustained overload.
How does the screw-terminal connection affect the 690 V AC rating?
Screw terminals accept solid or stranded conductors rated for 690 V AC, giving a secure connection at the full voltage rating.
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