Product Description:

The RD51.2-5B-018-L-DF-FW is a drive controller from Bosch Rexroth Indramat in the RD 500 Drive Controllers series. Designed for variable-speed regulation of induction motors used in automated machinery, the unit converts fixed mains power into a controlled output that meets real-time process demands during changing load conditions. Within an automation cell, it modulates motor frequency and voltage so conveyor lines, pumps, or fans can start, stop, and change speed under PLC command in continuous-duty production equipment.

Motor behavior is governed by the controller’s U/f curve control, a method that ties output voltage to frequency to preserve usable torque across the speed range. Thermal energy from internal electronics is removed by forced air cooling, allowing continuous service without derating in panel-mount enclosures. The power stage is sized for 18.5 kW, making it suitable for medium-horsepower drives in material-handling systems. DC-link surges are dissipated through a built-in brake chopper, preventing overvoltage during rapid deceleration cycles. The main power section is designed for a nominal line voltage of 500 V, providing compatibility with high-voltage factory grids while reducing current demand for a given load.

The unit uses a three-phase AC input, meaning the module rectifies three-phase mains before generating variable AC for the motor, a topology that simplifies harmonic filtering on the supply side. Control wiring terminates on a NAMUR terminal strip, and an external 24 V standby supply keeps control logic active during short mains interruptions and controlled shutdown events. Process supervision is improved by current filter feedback (U6, V6, W6), which enables verification of phase currents and supports protection monitoring. As part of Generation 2, the hardware includes updated gate-driver and diagnostic circuitry.