Siemens 3RT2028-1BB40 SIRIUS Power Contactor 38A 18.5kW 24V DC 3P

The Siemens 3RT2028-1BB40 is a SIRIUS 3RT2 series power contactor rated at 38 A and 18.5 kW at 400 V, designed for AC-3e/AC-3 motor switching duties. It features a 24 V DC control coil and built-in auxiliary contacts (1 NO + 1 NC), housed in a 3-pole size S0 frame with screw terminals.

Technical specifications:

• MLFB: 3RT2028-1BB40
• Manufacturer: Siemens
• Product line: SIRIUS
• Product type: Power contactor (3RT2)
• Size: S0
• Number of poles: 3
• Rated current AC-3 at 400 V: 38 A
• Rated current AC-3 at 500 V: 32 A
• Rated current AC-3 at 690 V: 21 A
• Rated current AC-1 at 400 V / 40 °C: 50 A
• Rated power AC-3 at 400 V: 18.5 kW
• Rated power AC-3 at 230 V: 11 kW
• Operating voltage (main circuit): up to 690 V AC
• Control supply voltage: 24 V DC
• Coil closing/holding power: 5.9 W
• Auxiliary contacts: 1 NO + 1 NC
• Terminal type: Screw terminal
• Insulation voltage (main and auxiliary circuit): 690 V (pollution degree 3)
• Surge voltage resistance: 6 kV
• Mechanical service life: 10,000,000 operating cycles
• Operating temperature: -25 to +60 °C
• Storage temperature: -55 to +80 °C
• Maximum installation altitude: 2,000 m
• Net weight: 610 g

Features and benefits:

• 24 V DC coil with a wide operating range of 0.8 to 1.1 x rated voltage for reliable switching in DC control systems
• Built-in 1 NO + 1 NC auxiliary contacts eliminate the need for a separate auxiliary switch block in standard applications
• 10 million mechanical operating cycles service life ensures long-term reliability in high-cycle applications
• Compatible with electronically optimized auxiliary switch blocks and communication function modules for flexible system integration
• Short closing delay (50-170 ms) and opening delay (15-18 ms) at DC for predictable switching behaviour

Applications:

• Direct-on-line motor starting for 3-phase motors up to 18.5 kW at 400 V
• Motor control centres and industrial switchgear panels operating on 24 V DC control voltage
• AC-3e/AC-3 duty switching of induction motors in conveyor, pump, and fan applications
• DC load switching using series current-path configurations up to 690 V

Compliant with EN/IEC 60947-4-1. Part of the Siemens SIRIUS 3RT2 range.

Also known as: Siemens 3RT2028-1BB40, SIRIUS 3RT2 power contactor 38A, Siemens S0 contactor 24V DC.