Siemens 3RT2025 S0 Electromechanical Contactors
Siemens 3RT20252KB40 system placement
The 3RT2025 series occupies the S0 size class in Siemens power-contacting infrastructure, intended for panel DIN-rail or chassis mounting in motor-branch and lighting-control applications. The seed unit ships in bulk packaging with auxiliary contacts included as standard.
Siemens 3RT20252KB40 specifications
Coil parameters
| Parameter | Value |
|---|---|
| Coil Voltage | 24 VDC |
| Coil Power | 4.5 W |
| Coil Current | 187.5 mA |
| Coil Resistance | 128 Ω |
| Must Operate Voltage | 16.8 VDC |
The 24 VDC coil places this unit in the low-voltage DC control-circuit range common to PLC-output modules and industrial 24 V bus architectures.
Contact and mechanical data
| Parameter | Value |
|---|---|
| Contact Form | 3PST-NO (3 Form A) |
| Contact Rating | 40 A |
| Mounting | Chassis Mount, DIN Rail |
| Features | Auxiliary Contacts (1NO/1NC) |
| Encapsulation | Bulk |
The contact rating of 40 A and 3PST-NO configuration suit three-phase load switching; auxiliary contacts enable status feedback without separate relay addition.
Parametric comparison with Siemens 3RT2025 alternates
Reader must qualify each alternate independently; numeric similarity does not imply interchangeability.
| MPN | Coil V | Coil W | Contact A | Must-Operate V | Encap |
|---|---|---|---|---|---|
| 3RT20252KB40 | 24 VDC | 4.5 | 40 A | 16.8 VDC | Bulk |
| 3RT20252KG40 | 125 VDC | 4.5 | 17 A | 87.5 VDC | Box |
| 3RT20252KF40 | 110 VDC | 4.5 | 17 A | 77 VDC | Box |
| 3RT20252KC80 | 34 VDC | 4.5 | 17 A | 23.8 VDC | Box |
| 3RT20252FB40 | 24 VDC | 5.9 | 17 A | 19.2 VDC | Box |
| 3RT20252BB40 | 24 VDC | 5.9 | 40 A | 19.2 VDC | Bulk |
| 3RT20252BM40 | 220 VDC | 5.9 | 17 A | 176 VDC | Box |
| 3RT20252AB00 | 24 VAC | 65 VA | 17 A | 19.2 VAC | Box |
| 3RT20252NB30 | 21–28 VAC/DC | 5.9 | 17 A | — | Box |
- 3RT20252BB40 shares the 40 A contact rating and bulk encapsulation but draws 5.9 W at 245.8 mA with a lower must-operate threshold; also ships in bulk.
- 3RT20252AB00 is the sole AC-coil variant in this group at 24 VAC / 65 VA, switching to a 40 ms operate time; contact rating drops to 17 A.
- 3RT20252NB30 covers a 21–28 V universal AC/DC band but omits must-operate voltage data; contact rating is 17 A.