Siemens 3TH20400BB4 Contactor Relay is a 24 V DC coil auxiliary contactor from the 3TH2 family, featuring four normally open (NO) auxiliary contacts. It uses screw-terminal connections for easy wiring and is built in the 40E frame size, enabling compact installation in control panels. Common applications include energizing solenoids or other low-power devices, interlocking circuits, and signaling within DC-controlled motor and automation systems, where a single coil can switch multiple channels through the four NO contacts.
