Product Description:

The RD42.1-4R-084-L is a control unit produced by Bosch Rexroth Indramat and assigned to the RD 500 Drive Controllers series. In automated material-handling cells, this controller regulates the stator frequency of connected induction motors so conveyor belts or pumps accelerate, cruise, and decelerate under program control. By processing feedback and executing ramp profiles internally, it removes the need for mechanical throttling devices while still interfacing with PLC command signals through standard I/O for coordinated starts, stops, and speed changes during routine machine operation.

The unit is designed for mains systems between 380 V to 480 V, allowing connection to common industrial low-voltage grids. A permissible fluctuation of ±10% input tolerance keeps the controller functional during moderate brownouts or overvoltage events that can occur when large equipment starts on the same supply. The power stage uses a 3-phase AC converter, so it rectifies and then inverts the line supply to generate a DC link and synthesized output waveform. Thermal management relies on forced air cooling, with a dedicated fan channel that moves air across the heat sinks and helps prevent derating at nominal currents. To minimize conducted interference, an integrated mains filter attenuates high-frequency switching noise before it can propagate back onto the supply bus.

The unit is supplied without a brake chopper; instead, excess kinetic energy is returned to the grid through the built-in energy recovery circuit, reducing panel heat and external resistor requirements during deceleration. The unit is generation 1, matching the first design release of this controller platform. It operates as a drive controller, accepting analog or fieldbus commands for torque or speed references while retaining standard fault, overload, and regenerative monitoring functions for connected motors.