Product Description:

The RD51.2-4B-005-L-DF-FW is a drive controller from Bosch Rexroth Indramat in the RD 500 Drive Controllers series. It is installed in industrial automation panels to convert fixed-frequency three-phase power into variable output voltage and frequency for induction motors. By sitting between the mains supply and the machine, the controller regulates motor speed, executes protective trips, and exchanges control signals with higher-level PLC logic. This arrangement allows the drive to adapt motor speed to changing process demands in applications that do not require direct line-frequency operation.

The unit delivers an output rating of 5.5 kW, which suits medium-frame pumps, fans, and conveyors. It is built for supply networks from 380 to 480 V and tolerates line variation of up to ±10% without derating. Heat is removed by forced-air cooling, so the enclosure must provide enough airflow to keep the power semiconductors within their temperature limits. A built-in brake chopper dissipates regenerative energy during rapid deceleration, which can reduce the need for separate braking hardware. Motor excitation is controlled by U/f curve control, which helps keep air-gap flux stable across the speed range for predictable low-speed torque.

Incoming power reaches the controller through a three-phase AC converter input, and an integrated mains filter helps suppress conducted EMI on the supply line. Hardware generation 2 includes updated firing circuits and diagnostic functions. A NAMUR terminal strip carries 24 V standby power from an external source, allowing the control electronics to remain active when the main supply is disconnected. That arrangement supports status retention and communication availability during controlled shutdown or service isolation of the main power section. Additional terminals provide feedback for current filter phases U6, V6, and W6, which supports external monitoring of harmonic and load conditions without separate measurement devices.