Product Description:

The RD51.1-4B-200-R-M1-FW/S139 drive controller is produced by Bosch Rexroth Indramat within the RD 500 Drive Controllers series. It serves as the central power stage that links a plant’s three-phase mains to asynchronous motors, regulating motor speed and torque for continuous-duty conveyors, mixers, and pump arrays. The unit interprets reference signals from higher-level PLCs and modulates the output frequency accordingly, allowing precise motion sequences while limiting mechanical stress. Because speed is controlled electronically, the drive can match motor output to changing process demand instead of running only at line frequency.

This first-generation design incorporates a built-in brake chopper that absorbs regenerated energy during rapid deceleration and protects the DC link. Its control core works with U/f curve control, delivering a proportional voltage-to-frequency profile that helps keep air-gap flux stable across the load range. For thermal management, the housing uses liquid cooling with an internal pump, which removes heat directly from the power modules and supports high duty cycles in compact cabinets. An integrated mains filter attenuates conducted emissions, so additional line filters are generally unnecessary. The converter is rated for up to 200 kW of output power, matching large process-drive applications.

Input energy is supplied through a three-phase AC converter that accepts line voltages from 380 to 480 V. Within this window, the controller tolerates line fluctuations of ±10 %, which helps reduce nuisance trips on weaker industrial grids. The unit is delivered without output chokes, so external output reactors are not part of the standard configuration. This arrangement reduces cabinet complexity and leaves more space for cable routing around the drive. The mains interface is suited to installations where supply conditions vary during normal plant operation.