TeSys Ultra control unit for motor protection and advanced functions
It handles motor power ratings of 18.5 kW at 400...440 V AC, 18.5 kW at 500 V AC, and 22 kW at 690 V AC, all at 50/60 Hz. The control circuit runs on 24 V DC, drawing 220 mA during closing and 80 mA sealed (with LUB38 interface). This unit provides protection against overload, short-circuit, phase failure, phase imbalance, and earth faults, with a manual reset. The thermal overload class is Class 20 with temperature compensation from -25 to 70 °C, conforming to IEC 60947-6-2 and UL 508. The tripping threshold is set at 14.2 x Ir ±20 %, and phase failure sensitivity is built in. Rated for AC-43 utilisation category, the LUCD38BL is suited for starting and stopping squirrel-cage motors with inching or plugging duty. Safe separation of circuits is maintained at 400 V SELV between control/auxiliary and main circuits per IEC 60947-1. The unit mounts via plug-in front face onto a compatible TeSys Ultra base, with IP20 protection on the front panel and wired terminals.
Standards compliance and environmental ratings
Environmental protection includes TH treatment conforming to IEC 60068 for tropical environments. Fire resistance is rated at 960 °C for parts supporting live components and 650 °C for other parts per IEC 60695-2-12. Operating altitude is limited to 2000 m. The unit withstands shock at 10 gn with power poles open and 15 gn with poles closed, and vibration at 2 gn (poles open) and 4 gn (poles closed) over 5-300 Hz. Immunity to microbreaks is 3 ms, and the unit withstands voltage dips of 70 % for 500 ms per IEC 61000-4-11. Resistance to fast transients is 2 kV class 3 on serial links and 4 kV class 4 on all other circuits per IEC 61000-4-4. Radiated field immunity is 10 V/m per IEC 61000-4-3.
The LUCD38BL is a plug-in front-face control unit for the TeSys Ultra system. Dimensions are 45 mm wide, 66 mm high, and 60 mm deep. It interfaces with the LUB38 control circuit interface for operating times of 35 ms opening and 70 ms closing. Heat dissipation is 3 W for the control circuit with LUB38. The unit supports communication and advanced functions beyond basic protection. It is designed for integration into motor control centres and panel builds where space is at a premium, given its compact 45 mm width. The plug-in design allows quick replacement without disturbing power wiring.