Siemens 3UA5900-2P Relay

Siemens 3UA5900-2P is a thermal overload relay designed to protect motors in Siemens motor-control circuits. It provides a 50–63 A trip range and uses a thermal mechanism to trip on overcurrent, helping prevent motor damage and electrical faults. The relay offers a single normally open and normally closed contact (1NO 1NC) for signaling or interlocking within control circuits, with reset available either automatically or manually to suit different start-up procedures. Wiring is through seven screw-clamp terminals, and the unit is intended for panel mounting in open enclosures; the contacts are silver-plated to reduce contact resistance and extend life. As part of the Siemens 3UA5x family of overload relays, the 3UA5900-2P is designed to accompany compatible Siemens protection schemes to safeguard motors in three‑phase power networks. Typical applications include motors in conveyors, pumps, fans, and other process or automation equipment where reliable overload protection is essential and integration with Siemens contactors and control gear is desired for a cohesive protection strategy.