Application Fit for 16A Auxiliary Switching
Before specifying any S00 contactor, verify that coil voltage aligns with your PLC output architecture. The 3RT25181BB40 operates on 24VDC with a 19.2VDC must-operate threshold—suitable for standard 24V industrial control circuits but requiring confirmation against your specific PLC module's sinking/sourcing capacity.
On-page parameter snapshot
- Contact Rating: 16 A
- Coil Voltage: 24VDC (Must-Operate: 19.2 VDC)
- Switching Voltage: 400VAC maximum
- Contact Arrangement: 4PST-2NO/2NC (2 Form A, 2 Form B)
- Coil Power: 4W (Coil Resistance: 144Ω)
- Operate Time: 100 ms / Release Time: 13 ms
- Operating Temperature: 25°C to 60°C
- Mounting: Chassis Mount, DIN Rail
- Termination: Screw Terminal
Coil Voltage Trade-offs Across the 3RT2518 Family
The 3RT25181BB40 sits within a family sharing identical 16A contact ratings and form factors but differing in coil voltage. The 24VDC coil draws 166.7mA and consumes 4W—lower power than the AC variant (37VA) but with a slower operate time of 100ms versus 35ms. If your application demands faster response for time-critical switching, the AC-coil variant (3RT25181AB00) offers 35ms operation. However, DC coils remain the standard for modern PLC architectures with solid-state output modules.
Procurement Notes
Engineer's notes — electrical baseline
Use siemens 3RT25181BB40 (CONTACTOR S00 16A 24VDC 2NO/2NC); category path: Relays > Contactors (Electromechanical); confirmed specs: series: 3RT2; Mounting Type: Chassis Mount, DIN Rail; Package: Bulk; Product Status: Active only after you have mapped its headline specs to the machine safety concept: supply rails, fault behavior, and any mandatory approvals implied by the raw fields—not generic catalog guesses.
Field notes — install and commissioning
Installation teams should capture photos/part markings for traceability and compare them to the MPN string above before closing the work order.
Selection notes — BOM and electrical class
Selection should explicitly record why this SKU beat adjacent catalog lines: which numeric limits or certifications in the raw row drove the pick.