Product Description:

The RD51.1-5B-003-L-DF-FW is a drive controller from Bosch Rexroth Indramat that belongs to the RD 500 Drive Controllers series. It regulates induction motors in automated machinery by converting fixed-frequency plant power into an adjustable output. Within an automation cell, the unit supplies variable voltage and frequency so conveyors, mixers, or small process pumps can match commanded speed profiles issued by a PLC, improving throughput while reducing mechanical stress on the driven equipment. Because the controller integrates power electronics and low-level scalar control, it also removes the need for external soft starters.

Incoming mains are connected to a three-phase AC converter front end, meaning the drive expects a symmetrical three-phase supply. The power section is rated for a nominal line of 500 V, allowing direct operation on common 480 V networks without an isolation transformer. At this voltage, the controller can deliver up to 3.0 kW of mechanical power to the motor, a range suited to compact conveyors, mixers, and similar process equipment. Speed regulation follows U/f curve control, so the drive maintains a fixed ratio between output voltage and frequency to help keep motor flux constant during low-speed operation. Internal components are kept within temperature limits by forced-air cooling, which expels heat through a dedicated fan channel.

A built-in brake chopper redirects regenerated energy to an external resistor during rapid deceleration, preventing DC-bus overvoltage. Control wiring is organized on a NAMUR terminal strip, and an auxiliary 24 V standby feed keeps logic circuits active when the main power is off. For real-time protection, the unit samples phase currents with current filter feedback (U6, V6, W6), enabling the PLC to react to overload or short-circuit events. The unit is part of Generation 1 hardware.