Product Description:

The RD51.1-4N-090-L-NN-FW is a drive controller manufactured by Bosch Rexroth Indramat and placed within the RD 500 Drive Controllers series. In an automation cell, this unit operates as the power conversion interface between a three-phase mains supply and an induction motor, regulating motor speed through open-loop voltage-to-frequency profiling so conveyors, pumps, or fans can match process demands without mechanical throttling. This operating method supports variable-speed applications that need consistent motor behavior across changing load conditions.

This model delivers a continuous mechanical output of 90 kW, which is suitable for medium-to-large production machinery. The input section accepts line potentials from 380 to 480 V and remains functional when the mains deviates by up to ±10 %, allowing stable operation with normal supply variation. The supply category is Converter 3 x AC, so the unit rectifies three-phase AC, stores energy on a DC link, and then recreates an adjustable three-phase waveform for the motor. Motor excitation follows a U/f curve control profile, which keeps the ratio of stator voltage to electrical frequency nearly constant throughout the speed range and helps avoid magnetic saturation at low frequencies.

Thermal management relies on forced air cooling, and a built-in fan moves cabinet air across the heat sink so rated current can be maintained at full ambient conditions. For electromagnetic compliance, the unit contains an integrated mains filter, which reduces conducted interference on the supply. Dynamic braking energy cannot be dissipated internally because the drive is supplied without a built-in brake chopper, so regenerative loads require external braking hardware or controlled deceleration. The unit is identified as Design 1, which indicates the first design version in the RD 500 lineup.