What this TeSys U control unit does in a motor branch
The Schneider Electric LUCB1XBLTQ is an advanced control unit in the TeSys U range, designed for basic motor protection with advanced functions and communication capability. It sits on the front face of a TeSys U power base via plug-in mounting, making it a field-swappable logic module for a motor starter or protection assembly. Rated for 0.25 kW at 400...440 V AC 50/60 Hz, it handles a 3-phase self-cooled motor load. The 24 V DC control circuit draws 60 mA sealed (80 mA with LUB32/LUB38 power bases) and peaks at 130 mA during closing with the LUB12 base. Protection coverage includes overload and short-circuit, earth fault, phase failure, and phase imbalance — all with manual reset. The thermal overload class is Class 10 per IEC 60947-6-2 and UL 508, with temperature compensation from -25 to 70 °C. Tripping threshold is set at 14.2 x Ir ±20 %, and the unit is sensitive to phase failure. Immunity to microbreaks is 3 ms, and it withstands voltage dips to 70 % for 500 ms per IEC 61000-4-11.
Panel fit and environmental ratings
IP20 protection on the front panel and wired terminals, IP40 on other faces outside the connection zone. The unit is TH-treated per IEC 60068 for tropical environments. Operating altitude is limited to 2000 m. Vibration resistance: 2 gn (poles open) and 4 gn (poles closed) across 5...300 Hz; shock resistance: 10 gn (poles open) and 15 gn (poles closed). Safe separation of circuits is maintained at 400 V SELV between control/auxiliary and main circuits per IEC 60947-1. Control circuit voltage limits: 20...27 V DC for operation, dropout at 14.5 V DC. Fire resistance: 960 °C for parts supporting live components, 650 °C for other parts per IEC 60695-2-12.