The LA4DFBQ is a TeSys D interface amplifier module — an electromechanical relay module that bridges a 24 V DC control signal to a 380...415 V AC control circuit. It sits top-mounted on a TeSys D contactor or starter, letting a low-voltage PLC or safety relay drive a higher-voltage load without a separate interposing relay. Rated supply voltage is 24 V DC, with a guaranteed state-1 threshold of 17 V and a state-0 voltage below 2.4 V. Coil current consumption is 25 mA at 20 °C, so the PLC output driving it needs at least that margin. Heat dissipation in the control circuit is 0.6 W — negligible for panel thermal budgeting. The module carries a LED indicator for local signalling of coil state, which speeds troubleshooting on a live panel without needing a meter.
Rated operational voltage on the control circuit is 380...415 V AC — that is the load side, not the coil. The module switches AC loads up to that voltage, so it suits motor contactor coils or valve actuators running on a 400 V three-phase panel. The insulation voltage rating is 250 V per IEC 60947-5-1, which governs the clearance and creepage for the control circuit. Electrical durability is 3 Mcycles at 240 V — that is the mechanical switching life under load. For a contactor interface that cycles every few seconds in a conveyor line, this translates to years of service before wear-out. The immunity to microbreaks is 4 ms, meaning the module ignores supply dips shorter than that, which is typical for industrial control.
Top-mounts directly onto a TeSys D contactor or reversing starter. Height is 12 mm (0.5 in), so it adds negligible stack height to the contactor assembly. The protective treatment is TH per IEC 60068, so it handles tropical humidity during storage.