Product Description:

The RD51.1-4N-055-L-C1-FW is a drive controller produced by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. It serves as the link between a plant power source and a standard induction motor by adjusting output voltage and frequency to suit the required operating speed. This allows conveyors, fans, pumps, and similar equipment to accelerate more smoothly and run at speeds that match the process instead of remaining at a fixed line frequency. In automated production lines, this type of control can reduce mechanical shock during starts and improve speed matching between connected machine sections.

The unit accepts a mains supply of 380 to 480 V through a 3 x AC converter input. It uses U/f curve control to maintain stable motor magnetization across the commanded speed range. The power section is rated at 55 kW, which suits medium-duty industrial loads such as larger blowers, pumps, and material-handling drives. Heat is removed by forced air cooling, allowing continuous operation at nominal current when cabinet airflow is properly managed. An integrated mains filter helps reduce conducted interference on the supply lines and supports cleaner installation in control cabinets. Because the filter is built in, external suppression components may be reduced in straightforward installations, and panel wiring remains less crowded.

The unit is design generation 1 and comes without a built-in brake chopper, so braking energy must be handled by an external resistor when regenerative operation is present. A DC-bus tolerance of ±10 % helps the drive remain operational during moderate supply variation. The control section also provides 24 V stand-by power for units up to 110 kW, which allows communication and stored settings to remain available during a mains interruption. That standby function supports continued control logic supervision and helps preserve network availability until the incoming supply returns.