Product Description:

The RD51.2-5B-005-L-A2-FW is a drive controller produced by Bosch Rexroth Indramat within the RD 500 Drive Controllers series. In automated plants, this unit sits between the main supply and an AC motor, shaping voltage and frequency so conveyors, pumps, or processing spindles run at the commanded speed and torque. It replaces mechanical throttling devices and lets the control system adjust motor performance directly through software. Because speed is set electronically, the drive can support smooth ramping, stable running conditions, and controlled deceleration without mechanical adjustment.

A key safety feature is the integrated built-in brake chopper, which diverts excess DC-bus energy into a resistor bank during quick deceleration to keep link voltage within limits. Speed regulation follows U/f curve control, so the voltage-to-frequency ratio remains constant and motor flux stays stable across the speed range. Thermal management is handled by forced air cooling, which moves heat away from the power semiconductors and supports continuous operation at the controller’s 5.5 kW rated output. The unit is sized for mains networks up to 500 V, matching many industrial 480 VAC installations and allowing normal supply variation without immediate derating.

This model belongs to design generation 2 and uses the second-generation RD layout, diagnostics, and option-board arrangement. It is built as a 3 × AC converter, so it rectifies three-phase input power and reconstructs a variable three-phase output on the inverter side. Control terminals include external stand-by power, which allows an auxiliary supply to keep the logic active when the main bus is off, and a starting lockout input that prevents unintended motor energization after power returns. These control connections help maintain operating status information and support a more orderly restart sequence after an interruption.