Product Description:

The RD51.1-5B-018-D-DF-FW is a drive controller manufactured by Bosch Rexroth Indramat in the RD 500 Drive Controllers series. It converts incoming three-phase utility power into regulated motor voltage so induction motors can be speed-controlled in automated material handling, pumping, and process equipment. By integrating power electronics, control logic, and braking hardware in one housing, the unit provides the central element of a variable-speed drive chain and links field devices to higher-level control systems in industrial automation platforms.

At its core, the controller uses U/f curve control to maintain a fixed volts-per-hertz ratio, enabling stable torque production across a broad frequency range without closed-loop feedback. The power stage is rated for 18.5 kW, which makes the device suitable for medium-sized pump or fan motors. A DC-link resistor is not required because a built-in brake chopper directs excess regenerative energy to an external brake resistor, preventing overvoltage events. Thermal management is handled by a plug-through cooler that transfers heat directly through the cabinet wall. This layout keeps interior temperatures low on frames up to 110 kW. The input section is intended for 500 V class networks typically found in high-power plants.

The supply connection uses a three-phase AC converter topology, so the rectifier, DC bus, and inverter are combined in a single module that only requires three line conductors and protective earth. Control wiring is simplified by the NAMUR terminal strip, which offers 24 V standby power and allows auxiliary circuits to remain active when the main bus is de-energized. Diagnostic data include current feedback from terminals U6, V6, and W6, providing a direct view of output line currents. The unit is design generation 1, which identifies the platform revision used for this controller.