3RT2018-1BB42

The SIRIUS 3RT2018-1BB42 miniature electromagnetic contactor features a 24V DC coil and one set of normally closed auxiliary contacts. It is suitable for DC control panels and PLC interlocking circuits. It is AC-3 7.5kW/400V, S00 standard frame, and weighs only about 0.291 kg.

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Siemens 3RT2018-1BB42 Electromagnetic Contactor, 24V DC Coil, 1NC Auxiliary Contact

Product Positioning

The 3RT2018-1BB42 is a small electromagnetic contactor from the Siemens SIRIUS 3RT20 series, driven by a 24V DC coil. It features a built-in normally closed (NC) momentary auxiliary contact for easy connection to interlocking circuits or status feedback signals. The main contact AC-3 has a rated current of 16A, corresponding to a 7.5kW motor load at 400V. It uses a standard S00 mounting frame and is compact, allowing direct pairing with a thermal overload relay from the same series to form a complete motor starter. The DC coil version is particularly suitable for automated machines primarily powered by 24V DC control, peripherals of solar inverter equipment, or battery-powered control boxes, eliminating the need for an additional AC/DC conversion module.

Core Product Advantages and Features

24V DC coil design

The coil has a rated voltage of 24V DC and can be directly connected to a PLC output module or a 24V control power supply without the need for an additional rectifier circuit, making it suitable for fieldbus control panels.

One set of normally closed auxiliary contacts (1NC)

Built-in instantaneous normally closed auxiliary contact can be used for interlocking protection, fault feedback or emergency stop circuit design to improve the system safety level.

S00 standard frame, screw terminals

It adopts the common S00 mounting dimensions and screw terminal wiring of SIRIUS 3RT20 series, which is convenient for combination with thermal overload relays and auxiliary contacts.

High mechanical life design

With a mechanical life of up to 30 million operating cycles, it has excellent long-term operational stability and reduces the maintenance frequency of small machines.

project	Specification
model	3RT2018-1BB42
coil voltage	24V DC
Auxiliary contact	1 NC (normally closed)
Rated operating current (AC-3)	16 A
Rated power (AC-3, 400V)	7.5 kW
Extreme number	3P
Mounting Frame	S00 (SIRIUS 3RT20 series)
Wiring method	Screw terminals
External dimensions (width × height × depth)	45×58×73 mm
weight	Approximately 0.291 kg
Mechanical life	30 million operation cycles
Rated insulation voltage	690V
Rated impulse withstand voltage	6 kV
Protection level	IP20 (front)
Operating ambient temperature	-25°C ~ +60°C (Storage temperature: -55°C ~ +80°C)