SIEMENS
SIEMENS 3RT20181BB42 contactor 24V DC 3P 16A 1NC
IEC magnetic contactor switches 16 A inductive loads at 24 V DC with a 1 NC auxiliary contact and screw terminals on DIN rail
- 24 V DC coil enables low-voltage control panels
- 16 A inductive rating handles motor starting currents
- 3-pole main contacts switch three-phase loads
- 1 NC auxiliary contact provides status feedback
- DIN-rail and surface mounting fits compact enclosures
SIEMENS 3RT20181BB42 IEC magnetic contactor
This SIEMENS 3RT20181BB42 contactor is a 3‑pole IEC magnetic starter rated for 16 A inductive and 22 A resistive loads. It operates on a 24 V DC coil and provides one normally closed auxiliary contact. The unit is designed for DIN rail or surface mounting in control panels and machine‑shop equipment.
Thermals noise and power draw in normal use
The contactor has no enclosure rating and no internal fan, so it relies on natural convection within the cabinet. Coil power consumption is limited to the 24 V DC control circuit, producing no audible noise during steady operation. Contacts are rated for the stated currents without additional derating in typical industrial environments.
Bundled accessories and software impact
The product ships as a single contactor with screw‑terminal connections for power and control wiring. No auxiliary contact blocks, surge suppressors or configuration software are included. Installers must provide their own DIN rail, wiring and any additional accessories required by the application.
Highlights
- 24 V DC coil enables low-voltage control panels
- 16 A inductive rating handles motor starting currents
- 3-pole main contacts switch three-phase loads
- 1 NC auxiliary contact provides status feedback
- DIN-rail and surface mounting fits compact enclosures
Specifications
| Brand | SIEMENS |
|---|
Questions about this item
How is the SIEMENS 3RT20181BB42 contactor mounted and wired, and what step is often missed?
Snap the S00 frame onto a DIN rail or surface-mount it, then tighten the screw terminals; the step often missed is verifying the coil is 24 V DC before applying power.
What maintenance or replacement will this contactor need over time?
The main power contacts and the single 1 NC auxiliary contact wear with switching cycles; plan to replace the complete unit when contact resistance rises or the auxiliary fails to break cleanly.
Which limit appears first during sustained operation at full inductive load?
The 16 A inductive current rating is the limiting factor; continuous operation at that level will reach the thermal limit of the S00 frame before the 22 A resistive rating becomes relevant.
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