3RT2023-1KB40

The Siemens 3RT2023-1KB40 coil has a built-in varistor (surge suppressor), DC24V, threaded terminals, and 1NO+1NC auxiliary contacts, which can reduce interference to the control circuit during power failure.

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Siemens 3RT2023-1KB40 DC24V Electromagnetic Contactor with Built-in Varistor 1NO+1NC 9A/4kW

Product Positioning

The 3RT2023-1KB40 is a version of the SIRIUS 3RT2 S0 frame contactor with a specially added "coil-integrated varistor (surge suppressor)". It features a DC 24V coil with threaded terminals, a main circuit AC-3 rated current of 9A, and a rated power of 4kW at 400V. Since a back EMF surge is generated when the coil is de-energized, if not suppressed, it may interfere with PLC output points or other electronic components in the same circuit over time. This model integrates a varistor across the coil to limit the surge voltage within a safe range, and is therefore often used as a coupling contactor directly driven by PLC digital outputs. The auxiliary contacts maintain the standard 1NO+1NC combination for easy acquisition of interlocking and status feedback signals.

Core Product Advantages and Features

Built-in varistor in coil

The coil is equipped with a varistor (surge suppressor) at both ends. When the power is cut off, the back electromotive force surge of the coil can be limited to a safe range, protecting the PLC output point and electronic components in the same circuit.

Suitable for direct drive of PLC output

After suppressing surges, the interference to the control circuit is reduced, and it is often classified as a coupling contactor that can be directly driven by the output point of a programmable controller (PLC).

DC24V, screw terminal

The coil has a rated voltage of 24V DC. The main circuit and auxiliary circuit adopt traditional screw terminal fastening, and the wiring is stable and suitable for existing distribution panels that require regular inspection.

S0 frame, AC-3 9A/4kW

The AC-3 three-pole main contact has a rated current of 9A, a rated power of 4kW at 400V, complies with IEC/EN 60947-4-1, and has a mechanical life of 10 million cycles.

project	Specification
model	3RT2023-1KB40
Coil rated voltage	DC 24 V
Coil type	DC electromagnetic coil with built-in varistor for surge suppression
Auxiliary contact configuration	1 NO + 1 NC (Instantaneous Type)
Wiring method	Screw terminal
Applicable Scenarios	Coupler contactor that can be directly driven by PLC output point
Rated operating current Ie (AC-3, 400V)	9 A
Rated operating power (AC-3, 400V)	4 kW
Main contact pole number	3-pole (3NO)
Contactor size class	S0
External dimensions (width x height x depth)	45 x 85 mm, depth approximately 97 mm (AC coil) or 107 mm (DC coil) depending on coil type.
Rated insulation voltage Ui	690 V
Mechanical life	10 million cycles
Protection level	IP20 (Front-side touch protection, conforms to finger-proof electric shock structure)

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