Product Description:

The RD51.1-4N-018-L-V1-FW is a drive controller manufactured by Bosch Rexroth Indramat and supplied as part of the RD 500 Drive Controllers series. It serves as the central converter in variable-speed induction motor systems, translating three-phase line power into a regulated output that matches changing process demands. In automated material-handling, packaging, and pump applications, the unit provides the electrical interface between the plant power bus and the motor, allowing speed adjustment, controlled acceleration, and coordinated stopping without mechanical gear changes. This arrangement helps the connected motor respond smoothly to changing load conditions during normal operation.

It accepts a line voltage range of 380 to 480 V, operates as a three-phase AC converter, and delivers up to 18.5 kW of continuous motor power. The internal regulator uses U/f curve control, so motor flux stays proportional to frequency, which suits standard squirrel-cage machines and straightforward speed regulation. Heat is removed by forced-air cooling, with ducted fans guiding airflow across the heat sinks to keep semiconductor temperatures within their operating limit. Electromagnetic interference returning to the supply is reduced by an integrated line filter, which allows the controller to connect directly to plant distribution panels without an added external filter.

Incoming supply variation is tolerated within ±10 % of nominal, allowing the converter to remain stable during moderate overvoltage or undervoltage conditions. The unit comes without a built-in brake chopper, so regenerative braking energy must be handled by an external resistor module or returned to upstream equipment. An external control cabinet can provide the 24 V standby power input, which keeps the control electronics active for communication and parameter retention when the main line contactor is open. Keeping the control section energized in that state also supports status monitoring while motor power is disconnected.