Siemens 3RT20172BB41: S00 Frame DC Coil Contactor
Key Specifications (3RT20172BB41)
| Parameter | Value |
|---|---|
| Coil Voltage | 24 VDC |
| Contact Rating | 12 A |
| Contact Form | 3PST-NO (3 Form A) |
| Coil Power | 4 W |
| Coil Current | 166.7 mA |
| Coil Resistance | 144 Ω |
| Must Operate Voltage | 19.2 VDC |
| Mounting | Chassis Mount, DIN Rail |
| Base Product Number | 3RT2017 |
| Encapsulation | Bulk |
The 3RT20172BB41 is a Siemens S00 frame power contactor with a 24 VDC coil. The 12 A contact rating applies to the three main poles configured as 3PST-NO. The coil draws 166.7 mA at rated voltage, with a must-operate threshold of 19.2 VDC (80% of nominal). Spring-loaded terminals provide the 1NO auxiliary contact arrangement.
Design Family: S00 Frame DC Coil Contactors
The S00 frame size defines the mechanical envelope and mounting footprint for this contactor series. All variants in the seed MPN prefix share the same chassis and DIN rail mounting provisions.
Voltage and Contact Variants
Alternate coils within the same frame range from 48 VDC to 125 VDC. The primary differentiator among family members is the auxiliary contact configuration: some variants carry 1NC instead of 1NO, while others offer 2NO/2NC configurations. The seed unit ships in bulk packaging with spring-type terminals for the auxiliary contact.
Electrical Parameters
Coil power dissipation remains constant at 4 W across voltage variants, while coil current scales inversely with applied voltage. The must-operate voltage scales proportionally (approximately 80% of nominal coil voltage) to ensure reliable pickup across operating conditions.
Compare: Seed vs. Family Voltage Variants
| Spec | 3RT20172BB41 (seed) | 3RT20172BW41 | 3RT20172BE41 | 3RT20172BG41 |
|---|---|---|---|---|
| Coil Voltage | 24 VDC | 48 VDC | 60 VDC | 125 VDC |
| Contact Rating | 12 A | 12 A | 12 A | 12 A |
| Contact Form | 3PST-NO | 3PST-NO | 3PST-NO | 3PST-NO |
| Mounting | DIN / Chassis | DIN / Chassis | DIN / Chassis | DIN / Chassis |
| Similarity | 1.00 | 1.00 | 1.00 | 1.00 |
Reader must qualify alternate contactors independently; numeric similarity does not imply interchangeability. The 3RT20172BW41 shares the same auxiliary contact form but operates at 48 VDC; the 3RT20172BE41 uses 60 VDC; the 3RT20172BG41 targets 125 VDC applications. All four are mechanically compatible S00 frame units.
Engineering Verification Checklist
- Confirm system nominal DC supply voltage matches coil rating (24 VDC)
- Verify must-operate voltage (19.2 VDC) is met under worst-case supply conditions
- Check that 12 A contact rating suits the controlled load type and duty cycle
- Validate DIN rail or chassis mounting compatibility with existing panel layout
- Confirm auxiliary contact configuration (1NO spring) matches control circuit requirements
- Verify bulk packaging quantity aligns with procurement or inventory needs
- Compare lead-length and terminal torque specifications for field wiring
- Assess coil suppression requirements if driving from solid-state outputs
- Confirm operating temperature range is appropriate for the installation environment