SIEMENS
SIEMENS 3RU21160CB0 Overload Relay 0.18-0.25 A 690 V AC
Thermal overload relay protects motors at 0.18–0.25 A up to 690 V AC with auto or manual reset
- Thermal overload protection for motors up to 0.25 A
- Trip Class 10 ensures reliable response to sustained overcurrents
- 690 V AC rating suits industrial control circuits
- Direct contactor mounting simplifies panel assembly
- Auto and manual reset modes give flexible recovery
Application & Compatibility
The SIEMENS 3RU21160CB0 is a thermal overload relay designed for three-phase motor protection in industrial control panels. It mounts directly onto SIRIUS series contactors in frame size S00 and provides adjustable current monitoring from 0.18 A to 0.25 A. The unit suits maintenance engineers and panel builders who need reliable overload detection on 690 V AC systems.
Thermals, Noise & Power Draw
This relay operates without fans or active cooling, so it produces no audible noise during normal operation. Power consumption is limited to the heating effect of the monitored motor current passing through its three thermal elements. The screw-terminal connections ensure stable contact resistance, keeping self-heating low within the 0.18 A to 0.25 A setting range.
Sustained Load Behaviour
Under continuous overload the thermal elements trip at Trip Class 10 response speed, opening the 1NO/1NC auxiliary contacts to de-energise the contactor coil. The relay can be reset manually or automatically once the elements cool, allowing flexible restart policies. Because protection is purely thermal, repeated sustained overloads do not degrade the trip characteristic or calibration.
Highlights
- Thermal overload protection for motors up to 0.25 A
- Trip Class 10 ensures reliable response to sustained overcurrents
- 690 V AC rating suits industrial control circuits
- Direct contactor mounting simplifies panel assembly
- Auto and manual reset modes give flexible recovery
Specifications
| Brand | SIEMENS |
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Questions about this item
How do I mount the 3RU21160CB0 directly to a SIRIUS contactor and which step is often missed?
Align the relay with the contactor’s built-in rail, tighten the three screw terminals to the specified torque, then fit the three included thermal units — skipping the thermals is the common error.
Which parts of the 3RU21160CB0 will need replacement after repeated trips?
The three thermal units are the wear items; they must be replaced after sustained overloads cause them to fatigue, while the relay body and 1NO/1NC auxiliary contacts remain serviceable.
At what current does the 3RU21160CB0 trip first during a continuous overload?
The relay trips when current exceeds the 0.25 A maximum setting under Trip Class 10 timing, which is the first limit reached before the 690 V AC voltage rating becomes a factor.
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