Siemens 3TH4391-0BB4 Relay

Siemens 3TH4391-0BB4 is a 10‑pole contactor relay from the 91E family with a 24 V DC coil and a 10 A contact rating. It provides nine normally open (NO) contacts and one normally closed (NC) contact for versatile control logic, ideal for panel wiring and automation sequences. The device adheres to EN 50011 (IEC control circuits) and uses screw terminals for dependable connections. Identified by the 3TH4391-0BB4 designation, it sits in Siemens' 3TH4‑series of control relays designed to interface with PLCs and other automation devices. The compact form is dimensioned at approximately 78 mm high, 55 mm wide, and 135 mm deep, offering a compact footprint for space‑constrained control panels. With a 24 V DC coil, this relay switches its 10 A contacts under DC control inputs, enabling reliable signaling and interlocking in industrial applications such as machine control, sequencing, and safety interlocks.