The Schneider LUCB12FUTQ is an advanced control unit in the TeSys U range — the brain of a motor starter that combines protection and control in one plug-in module. It sits on the front face of a TeSys U power base and handles the logic: overload protection, short-circuit detection, phase failure sensing, and earth fault protection, all in one package. It's rated for 5.5 kW at 400...440 V AC, and can go up to 9 kW at 690 V AC — so it covers a solid spread of standard three-phase motor loads, from pumps and fans to small conveyors. The thermal overload is Class 10, meaning it trips fast enough to protect a motor during a stalled-rotor condition without nuisance tripping on a normal start. The control voltage is 110...240 V AC or 110...220 V DC, which is common for panel supplies in most industrial plants. Manual reset means someone has to go to the starter and push the button after a trip — that's the safe choice for unattended or hazardous-area machinery where you don't want an automatic restart.
The LUCB12FUTQ plugs into a TeSys U power base (like the LUB12 or LUB32) — no wiring between the control unit and the power base, just snap it on. That plug-in design means you can swap a control unit without touching the power wiring, which saves time during commissioning or if you need to change the protection settings later.
Protection and performance details
The unit provides protection against phase failure and phase imbalance, earth faults, overload, and short-circuit — all the essentials for a three-phase motor. The tripping threshold is 14.2 x Ir ±20%, which is typical for magnetic short-circuit protection in a motor starter. Operating time is 35 ms opening and 50 ms closing with the LUB12, LUB32, or LUB38 control circuit — fast enough for most motor protection applications. The unit is immune to micro-breaks up to 3 ms and voltage dips down to 70% for 500 ms, so it won't nuisance-trip on a brief line disturbance.