Product Description:

The RD51.1-4B-018-D-D1-FW is a drive controller produced by Bosch Rexroth Indramat and assigned to the RD 500 Drive Controllers series. Installed between a three-phase supply and an induction motor, it varies frequency and voltage so manufacturing cells, pumps, or conveyor sections can be tuned to process demands. This arrangement lets the drive adapt motor speed to changing production conditions without relying on mechanical throttling or fixed-speed operation. The controller combines power conversion, braking, and interface functions inside one enclosure, reducing the need for separate external modules while maintaining reliable torque regulation during continuous-duty operation.

This model delivers a rated output of 18.5 kW, matching medium-frame motors that require stable shaft power during speed changes and steady process control. It is fed from a mains window of 380 to 480 V and uses a three-phase AC converter supply, so incoming line power can be rectified and modulated internally for variable-frequency motor operation. The device tolerates line fluctuations of ±10 %, which helps it remain functional on industrial networks with changing loads or transformer tap variations. Motor flux is regulated by a U/f curve control method, an open-loop approach that helps preserve the magnetic field at lower frequencies and supports constant torque at reduced speeds.

Dynamic stopping energy is dissipated by a built-in brake chopper, eliminating the need for a separate switching stage for braking control. Thermal management is handled by a plug-through cooler, which transfers heat outside the cabinet and helps reduce the thermal load on surrounding components. Input distortion is reduced by an integrated mains filter that suppresses conducted emissions at the supply connection. Field wiring is simplified by a NAMUR terminal strip, and an external 24 V standby supply keeps the control electronics active when the main power is isolated. The unit is in design generation 1.