Siemens Sirius 3RF2 Solid-state contactor, screw, 3-phase, 1200V Part number 3RF2420-1AC45

Product Overview

The Siemens 3RF2420-1AC45 is a SIRIUS 3RF2-series 3-phase solid-state contactor designed for switching AC loads in industrial control and automation systems. It provides silent, wear-free switching of three-phase circuits without mechanical contacts — ideal for frequent switching, motor control, heating loads or other AC circuits requiring high reliability and long service life. Its 3-pole design and screw-terminal connections make it suitable for robust installation in control panels and switchboards.

Key Features

• 3-phase solid-state contactor (3 poles)
• Rated operational current: 20 A (AC-51, 40 °C)
• Wide load voltage range: 48 … 600 V AC
• Control input voltage: 4 … 30 V DC
• Screw-terminal main circuit connections — robust for industrial wiring
• Zero-voltage switching (thyristor-based) for silent, contact-free operation
• Blocking voltage (off-state) up to 1200 V — suitable for high-voltage AC systems
• Compact SIRIUS 3RF2 housing for DIN-rail or panel mounting
• Suitable for frequent switching cycles and continuous operation without mechanical wear

Technical Specifications

• Article Number: 3RF2420-1AC45
• Product Family: SIRIUS 3RF2 solid-state contactors
• Number of Poles (Main Circuit): 3 (three-phase)
• Rated Operational Current (AC-51, 40 °C): 20 A
• Load Voltage Range (Ue): 48 … 600 V AC
• Control Input Voltage (Us): 4 … 30 V DC
• Blocking Voltage (Off-state): 1200 V
• Switching Technology: Thyristor — zero-voltage switching (semi-conductor contactor)
• Main Contact Configuration: 3 × Normally Open (NO), no mechanical contacts (solid-state)
• Connection Terminals: Screw terminals for main circuit conductors
• Protection Class: IP20
• Ambient Operating Temperature: 0 … 40 °C (standard rating at 40 °C) with derating as specified
• Suitable Load Types: Resistive, inductive, motor loads (when correctly controlled), heaters, etc.
• Mounting: DIN-rail or panel mount (as per SIRIUS 3RF2 design guidelines)

Compliance & Certifications

• Designed as part of the SIRIUS 3RF2 solid-state switching device family — industrial-grade quality and reliability
• Solid-state switching avoids mechanical wear — suitable for frequent switching and automation applications
• Suitable for installation in industrial control panels, switchboards and motor control centers under standard low-voltage regulations

Applications

The 3RF2420-1AC45 is ideal for silent and reliable switching of three-phase AC loads — such as heaters, resistive and inductive loads, pumps, fans, motor circuits (when coordinated with overload protection), and general automation loads where maintenance-free operation is required. It is especially useful in environments requiring high switching frequency, low noise, or where mechanical contact wear must be avoided. Typical uses include HVAC systems, heating installations, conveyor drives, panel-mounted load switching, and industrial automation control systems.