Siemens Power contactor, 3 pole, 1NO + 1NC, size S0, 18.5KW Part number 3RT2028-1FB40

Product Overview

The Siemens 3RT2028-1FB40 is a SIRIUS 3RT2 series size S0 power contactor, configured for 3-pole switching of AC motors and loads. It is rated for a continuous current of 38 A at 400 V AC (AC-3) and a power rating of 18.5 kW in that condition. The coil is 24 V DC and includes an integrated diode, and the unit has auxiliary contacts for indication and control.

Key Features

• Power contactor from the Siemens SIRIUS 3RT2 product line, size S0
• 3-pole switching for standard three-phase motor circuits
• Rated operational current AC-3: 38 A at 400 V AC
• Rated power: 18.5 kW at 400 V AC (AC-3)
• Control coil: 24 V DC with integrated diode for suppression
• Auxiliary contacts: 1 NO + 1 NC for signaling and control feedback
• Screw-type terminals for secure wiring in industrial environments
• Compact size S0 for efficient panel or DIN-rail mounting

Technical Specifications

• Product Series: SIRIUS 3RT2
• Article Number: 3RT2028-1FB40
• Size Designation: S0
• Main Contacts: 3 × Normally Open (NO)
• Auxiliary Contacts: 1 × NO + 1 × NC
• Rated Operational Current (AC-3): 38 A at 400 V AC
• Rated Power (AC-3): 18.5 kW at 400 V AC
• Control Supply Voltage: 24 V DC (coil)
• Surge Withstand Voltage (Ui): 690 V
• Mechanical Service Life: ~10 000 000 operations
• Ambient Operating Temperature: –25 °C to +60 °C

Compliance & Certifications

• Manufactured by Siemens under the SIRIUS line of power switching devices
• Conforms to IEC/EN 60947-4-1 for contactors and motor-control equipment
• Designed for robust industrial usage with auxiliary signaling and compact size

Applications

Ideal for three-phase motor control, feeders and power distribution in industrial automation systems, manufacturing machines, HVAC units, and general mechanical equipment. The 3RT2028-1FB40 is particularly suitable where a compact size S0 contactor with integrated diode, auxiliary contacts and strong current/power rating is required.