Siemens 3RT2028-1BB40 Three-Phase Contactor 24V DC Coil

Siemens 3RT2028-1BB40 is a three-pole power contactor with a 24 V DC coil, designed for AC-3e/AC-3 duty, capable of switching up to 38 A (18.5 kW at 400 V) in a 3-pole configuration. It provides one normally open and one normally closed auxiliary contact (1 NO + 1 NC), uses screw terminals, and is offered in size S0 with upright mounting for straightforward wiring and secure installation. The 24 V DC coil supports control from standard low-voltage control circuits, enabling reliable starting and stopping of three-phase motors and other AC loads in automation cabinets and motor control centers. This Siemens contactor combines robust main contacts with an integrated auxiliary set to simplify interlocks and circuit wiring in medium-current motor control applications, delivering a documented 38 A / 18.5 kW at 400 V rating and compact S0 packaging. The DC-operated coil and fixed auxiliary contact arrangement are designed to streamline wiring in control panels and industrial machinery that rely on reliable, low-voltage control of medium-power motors.