Product Description:

The RD51.1-4B-004-P-NN-FW is a drive controller manufactured by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. Designed for induction-motor applications, the unit modulates output frequency and voltage so conveyors, pumps, and process machinery can be matched to changing load demands without mechanical gear changes. This allows smoother speed adjustment in systems that need variable motor output during normal operation. It is suited to installations where motor speed must track process conditions instead of running continuously at fixed line frequency.

This controller is supplied as a three-phase AC converter that draws three-phase mains and delivers variable output over a line window of 380 to 480 V. Input deviations of ±10% are acceptable, which helps the unit remain tolerant of normal supply fluctuations. It governs motor flux with U/f curve control, a method that keeps the voltage-to-frequency ratio more consistent so magnetizing current stays stable during speed changes. An integrated mains filter helps reduce conducted electromagnetic noise, and the controller is intended for straightforward analog or terminal-based control rather than fieldbus communication.

Thermal management is handled by a heat dissipation panel for drives up to 18.5 kW, which transfers switching losses directly to the cabinet wall and helps keep internal temperatures within permissible limits. This mounting approach moves heat away from the electronics without adding fan-driven airflow inside the enclosure. Dynamic braking energy is absorbed by a built-in brake chopper, eliminating the need for an external resistor interface in moderate-inertia drive applications. The unit belongs to design generation 1, which matches first-generation RD 500 accessory sets. The required application package is available separately rather than being preloaded on the controller.