Product Description:

The RD51.1-4B-090-L-NN-FW is a drive controller manufactured by Bosch Rexroth Indramat within the RD 500 Drive Controllers series. Intended for cabinet installation, it governs three-phase induction motors in automated production cells where precise speed adjustment is required. By modulating output voltage and frequency, the unit lets conveyors, pumps, and fans match process requirements while reducing energy use and mechanical stress. This operating approach makes it suitable for process lines that need adjustable motor speed without the complexity of closed-loop servo motion.

Rated to deliver 90 kW of mechanical output, the controller draws power through a three-phase AC converter rectifier stage. The permissible mains input is 380 to 480 V, and operation remains stable within a margin of ±10 % of that range. Speed and torque are regulated with U/f curve control, which links stator frequency to applied voltage in a simple open-loop method. Thermal losses are removed by forced-air cooling, so the full rating can be used when the airflow path remains unobstructed. The power section also includes an internal DC link that supports braking components and protective circuitry during changing load conditions.

A built-in brake chopper is connected across the DC link and switches excess energy to an external resistor during rapid deceleration, which helps prevent overvoltage faults. Line-side compliance is supported by an integrated mains filter that reduces conducted emissions without requiring a separate external filter cabinet. The hardware is part of Generation 1, matching the first mechanical layout used for the RD 500 platform. This arrangement is useful in applications with frequent starts, stops, or speed changes, where regenerated energy and input noise both need to be managed within the same controller enclosure.