Siemens 3RT20182BB41 S00 Power Contactor
The Siemens 3RT20182BB41 is a three-pole, S00-frame power contactor with a 24 VDC magnet coil, rated 16 A per pole and configured with one normally-open auxiliary contact (1NO). The suffix "BB" in the 3RT ordering code denotes the spring-clamp terminal execution, which is a common panel-builder preference for tool-free wiring in DIN-rail or chassis-mount arrangements.
Key Specifications
| Parameter | Value |
|---|---|
| Coil Voltage | 24 VDC |
| Must Operate Voltage | 19.2 VDC |
| Coil Power | 4 W |
| Coil Current | 166.7 mA |
| Coil Resistance | 144 Ω |
| Contact Form | 3PST-NO (3 Form A) |
| Contact Rating (Current) | 16 A |
| Base Product Number | 3RT2018 |
| Mounting Type | Chassis Mount, DIN Rail |
| Encapsulation | Bulk |
| Features | Auxiliary Contacts |
Contact Arrangement and Coil Class
The contactor provides three main power poles (3PST-NO) for switching AC or DC motor loads, plus one integrated auxiliary contact. The must-operate voltage of 19.2 VDC represents 80 % of the rated coil voltage, which is a standard pickup threshold for DC-operated contactors in industrial control circuits.
Coil Impedance and DC Drop-Out Behavior
Because the coil draws a continuous 166.7 mA at 24 VDC (4 W steady-state), the engineer should account for:
- Drop-out reliability: DC coils require a defined minimum voltage to hold closed. The record lists the must-operate threshold; any voltage sag below that level may cause dropout during brownout conditions.
- Coil resistance of 144 Ω provides a reference for in-circuit continuity checking.
Auxiliary Contact Function
The built-in 1NO auxiliary contact is suitable for signaling the contactor's status to a PLC input module or an indicator circuit. The spring-terminal execution on the BB suffix generally applies to both power and auxiliary terminals, simplifying field wiring.
Installation and Cabinet Integration
- S00 size (Sirius Mini) is one frame size smaller than the standard S2, fitting compact enclosures where panel space is constrained.
- Mounting options listed are chassis mount and DIN rail (35 mm top-hat rail per EN 60715), which are typical for motor branch panels.
- The contactor's DC coil requires a clean, regulated 24 VDC supply; engineers should verify supply ripple and short-circuit coordination if the coil feed shares a bus with other DC loads.
In-Catalog Comparison Rows (Reader Qualification Required)
The following rows share the same base product number, coil power, current rating, and mounting type. Differences in coil voltage, contact arrangement, or encapsulation type are noted; the reader must perform their own application qualification before substitution.
| MPN | Coil Voltage | Main Contact | Encapsulation | Must Operate Voltage |
|---|---|---|---|---|
| 3RT20182BB41 (primary) | 24 VDC | 3PST-NO + 1NO aux | Bulk | 19.2 VDC |
| 3RT20182BB42 | 24 VDC | 3PST-NO + 1NC aux | Bulk | 19.2 VDC |
| 3RT20182BB410CC0 | 24 VDC | 3PST-NO + 1NO aux | Box | 19.2 VDC |
| 3RT20182BB420CC0 | 24 VDC | 3PST-NO + 1NC aux | Box | 19.2 VDC |
| 3RT20182BF41 | 110 VDC | 3PST-NO + 1NO aux | Box | 88 VDC |
| 3RT20182BE41 | 60 VDC | 3PST-NO + 1NO aux | Box | 48 VDC |
| 3RT20182BW41 | 48 VDC | 3PST-NO + 1NO aux | Box | 38.4 VDC |
| 3RT20182BM41 | 220 VDC | 3PST-NO + 1NO aux | Box | 176 VDC |
| 3RT20182BB443MA0 | 24 VDC | 2NO/2NC aux contact block | Box | 19.2 VDC |
Why Each Variant Differs
- 3RT20182BB42 replaces the auxiliary normally-open contact with a normally-closed (NC) contact — appropriate when the auxiliary is wired for a trip or interlock function.
- 3RT20182BF41 / BE41 / BW41 / BM41 target different DC supply systems; the coil voltage varies from 48 VDC up to 220 VDC while maintaining the same 4 W coil power class.
- 3RT20182BB443MA0 adds a dedicated 2NO/2NC auxiliary contact block, increasing signaling flexibility at the cost of a larger termination footprint.
- Box vs. Bulk encapsulation refers to the supplied packaging format; no electrical difference is implied.