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3RT2018-1FB44-3MA0
Siemens 3RT2018-1FB44-3MA0 available at EU Automation. Get in touch today for a quick price.
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3. Your quote
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Siemens 3RT2018-1FB44-3MA0 is a SIRIUS S00 power contactor designed for dependable switching of three-phase loads in control panels and industrial installations. It features a 3‑pole main circuit with 3 normally open (NO) power contacts, plus permanently fitted auxiliary contacts (2 NO + 2 NC) for signalling and interlocking functions. The contactor is operated by a 24 V DC coil with an integrated suppression diode, helping to reduce switching transients in DC control circuits.
Rated for insulation voltages up to 690 V, it supports 22 A in AC‑1 duty (at 400 V, 40 °C) and 16 A in AC‑3 duty, making it well suited to motor control applications up to 7.5 kW at 400 V. IP20 protection on the front and finger-safe design support use in enclosed assemblies. Screw-type terminals are provided for both main and control connections, and the compact 45 mm width allows efficient side-by-side mounting on a 35 mm DIN rail or by screw fixing.
Rated for insulation voltages up to 690 V, it supports 22 A in AC‑1 duty (at 400 V, 40 °C) and 16 A in AC‑3 duty, making it well suited to motor control applications up to 7.5 kW at 400 V. IP20 protection on the front and finger-safe design support use in enclosed assemblies. Screw-type terminals are provided for both main and control connections, and the compact 45 mm width allows efficient side-by-side mounting on a 35 mm DIN rail or by screw fixing.
| Specification | Description |
|---|---|
| Manufacturer | Siemens |
| Part Number | 3RT2018-1FB44-3MA0 (alternative format: 3RT20181FB443MA0) |
| Product Range | SIRIUS |
| Product Type | Power contactor |
| Contactor Size | S00 |
| Poles (Main Circuit) | 3-pole |
| Main Contact Configuration | 3 × NO (normally open) |
| Auxiliary Contacts | 2 × NO + 2 × NC (captive / integrated auxiliary switch) |
| Control Supply (Coil) | 24 V DC |
| Integrated Coil Suppression | Diode (integrated) |
| Coil Operating Range | 0.8 … 1.1 × rated control voltage |
| Coil Power (Pull-in) | 4 W |
| Coil Power (Holding) | 4 W |
| Rated Insulation Voltage (Ui) | 690 V |
| Rated Impulse Withstand Voltage (Uimp) | 6 kV |
| Rated Operational Voltage (AC-3) | Up to 690 V |
| Rated Operational Current (AC-1) | 22 A at 400 V (40 °C); 20 A at 60 °C |
| Rated Operational Current (AC-3) | 16 A at 400 V; 12.4 A at 500 V; 8.9 A at 690 V |
| Motor Rating (AC-3) | 7.5 kW at 400 V |
| Protection Rating (Front) | IP20 |
| Touch Protection (Front) | Finger-safe (front access) |
| Mechanical Service Life | Typical 10,000,000 operating cycles |
| Mounting | Screw mounting and snap-on mounting to 35 mm DIN rail (DIN EN 60715) |
| Mounting Orientation | ±180° rotation on vertical surface; tilt ±22.5° forward/back |
| Terminal Type | Screw-type terminals (main, auxiliary and coil) |
| Conductor Cross-Section (Main Contacts) | Solid/stranded: 0.5 … 4 mm²; finely stranded with end sleeve: 0.5 … 2.5 mm² |
| Conductor Cross-Section (Aux Contacts) | Solid/stranded: 0.5 … 4 mm²; finely stranded with end sleeve: 0.5 … 2.5 mm² |
| Dimensions (W × H × D) | 45 mm × 58 mm × 117 mm (approx.) |
| Weight | Approx. 0.346 kg |
| Operating Temperature | -25 … +60 °C |
| Storage Temperature | -55 … +80 °C |
| Installation Altitude | Up to 2,000 m above sea level |
What does this power contactor do in a control panel?
It is an electromechanical switching device used to connect and disconnect a three-phase power circuit (typically a motor feeder) using a low-voltage control signal.
What is the rated operational current and application category?
It is rated up to 16 A in AC-3 duty (motor switching) at 400 V, and 22 A in AC-1 duty (resistive/low-inductance loads) at 400 V (at 40 °C ambient).
What motor power can it switch?
For typical motor switching (AC-3), it is suitable for up to 7.5 kW at 400 V.
What coil voltage does it require?
The control coil is 24 V DC, with an operating range factor of 0.8 to 1.1 of rated voltage.
Does the coil include surge suppression?
Yes. The coil has an integrated diode for surge suppression. Because it is diode-based, correct polarity must be observed when wiring the coil terminals (A1 positive, A2 negative).
How many main power poles and main contacts are provided?
It is a 3-pole contactor with 3 normally-open (NO) main contacts for switching a three-phase circuit.
What auxiliary contacts are included?
It includes a captive (built-in) auxiliary contact set of 2 NO + 2 NC instantaneous contacts for control and signalling duties.
What are the auxiliary contact ratings for control circuits?
Typical auxiliary ratings include AC-15: 6 A at 230 V and 3 A at 400 V; DC-13: 6 A at 24 V, 1 A at 110 V, and 0.3 A at 220 V.
What is the insulation and voltage capability of the main circuit?
The rated insulation voltage is 690 V, and the impulse voltage withstand is 6 kV.
What ingress protection does it provide?
The front protection class is IP20, with finger-safe touch protection from the front.
How is it mounted in an enclosure?
It is suitable for screw mounting or snap-on mounting onto a 35 mm standard DIN rail (DIN EN 60715). Side-by-side mounting is permitted (0 mm side spacing), with recommended clearance to the front/up/down as specified by the installation guidelines.
What are the approximate dimensions?
Overall dimensions are approximately 45 mm wide, 58 mm high, and 117 mm deep.
What cable sizes can be connected to the terminals?
Main and auxiliary screw terminals accept solid or stranded conductors typically from 0.5 to 4 mm² (fine-stranded with end sleeves typically 0.5 to 2.5 mm²).
What is the typical mechanical endurance?
Typical mechanical life is about 10,000,000 operating cycles for the contactor mechanism.
Are there recommendations for short-circuit protection coordination?
Yes. Typical gG fuse guidance for the main circuit is 50 A for coordination type 1 and 25 A for coordination type 2 (exact selection depends on prospective short-circuit current and installation conditions).
How should I describe this item on documentation or a bill of materials?
A clear description is: three-pole power contactor, size S00, 24 V DC coil with integrated diode, AC-3 16 A (7.5 kW at 400 V), built-in 2NO+2NC auxiliary contacts. If needed, you can add the ordering reference 3RT2018-1FB44-3MA0 in the line item.
- Switching and controlling three-phase motors up to 7.5 kW at 400 V in industrial control panels
- Frequent start/stop duty for motor-driven equipment such as pumps, fans, compressors and conveyors
- Main power switching element in motor starter assemblies (paired with an overload protection device)
- Interfacing a 24 V DC control system to switch higher-voltage three-phase loads via the contactor coil
- Electrical isolation and controlled energising of machine sub-circuits during normal operation sequences
- Creating forward/reverse or changeover motor control arrangements when used in matched contactor pairs
- Building interlocked control circuits using the integrated auxiliary contacts for feedback and status signalling
- Controlling resistive or lightly inductive loads within the contactor’s AC-1/AC-5 utilisation categories
- Use in HVAC and building services panels for staged control of motors and associated plant
- Automation and OEM machinery builds requiring a compact S00 frame contactor with screw terminals and IP20 front protection
This content has been produced using multiple sources. EU Automation takes no responsibility for the accuracy of this information. Always consult the original equipment manufacturer for the most up to date instructions and information.
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