The LUCB18BLTQ is an advanced control unit in the TeSys U range, designed for motor control and protection of three-phase motors. It handles motor power ratings of 7.5 kW at 400...440 V AC, 9 kW at 500 V AC, and 15 kW at 690 V AC (50/60 Hz). This unit provides protection against overload, short-circuit, phase failure, phase imbalance, and earth fault. It features manual reset and a Class 10 thermal overload characteristic, temperature-compensated from -25 to 70 °C per IEC 60947-6-2 and UL 508. The control circuit runs on 24 V DC, drawing 220 mA peak during closing and 80 mA sealed. The control voltage limits are 20...27 V DC for operation, with dropout at 14.5 V DC.
Rated insulation voltage is 690 V per IEC 60947-6-2, 600 V per UL 60947-4-1 and CSA C22.2 No 60947-4-1. That 690 V figure means it can be used on 400 V systems with full headroom, and on 690 V systems where available. Utilisation categories AC-41, AC-43, and AC-44 cover resistive, motor, and severe motor duty. AC-44 is the heavy lifting category — switching motors with frequent starts and stops, which is the real-world load for conveyors and compressors. Tripping threshold is 14.2 x Ir ±20 %. That's the magnetic short-circuit trip point — set it via the power base's Ir rating, and the unit clears faults fast enough for coordination with upstream breakers. IP20 on the front panel and wired terminals, IP40 on the front panel outside the connection zone.
Plug-in mounting on the front face — it snaps onto the TeSys U power base (LUB32 or LUB38). Dimensions are 45 mm wide, 66 mm high, 60 mm deep. That 45 mm width is a single modular pitch on a DIN rail, so it fits standard panel layouts. The control circuit draws 3 W heat dissipation with either LUB32 or LUB38 base. Safe separation of circuits is 400 V SELV between control/auxiliary and main circuits per IEC 60947-1. That means the 24 V DC control wiring can share a cable tray with the power wiring without extra insulation barriers.
Certified to EN 60947-6-2, IEC 60947-6-2, UL 60947-4-1 (with phase barrier), and CSA C22.2 No 60947-4-1 (with phase barrier). The UL and CSA marks mean it is accepted in North American panels without additional evaluation. Fire resistance tested to 960 °C on parts supporting live components per IEC 60695-2-12, and 650 °C on other parts. Protective treatment is TH conforming to IEC 60068 for tropical environments. Immunity to fast transients is 2 kV class 3 on the serial link 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. Voltage dip immunity is 70 % for 500 ms per IEC 61000-4-11.