Product Description:

The RD51.1-4N-018-L-NN-FW is manufactured by Bosch Rexroth Indramat and belongs to the RD 500 Drive Controllers series. It is used in automation panels to adjust induction-motor speed and torque by modulating the output frequency delivered to the motor. In automated equipment, the unit works as the final control element between the power source and the motor, carrying out setpoints from a higher-level PLC to keep conveyors, pumps, and similar loads running steadily. This operating role makes it suitable for variable-speed process applications that need repeatable motor response under changing load conditions.

This model relies on U/f curve control, so voltage and frequency rise proportionally to help keep motor flux constant across the speed range. Thermal management is handled by forced air cooling, and a factory-mounted fan moves air through internal channels to remove switching losses from the IGBTs. Electrical noise at the line side is limited by an integrated mains filter, which reduces conducted emissions without extra cabinet hardware. The drive is sized for a continuous output of 18.5 kW, matching medium-frame motors used in common industrial drive applications. It accepts line voltages from 380 to 480 V, allowing direct connection to common industrial power systems without an autotransformer.

The unit requires a 3-phase AC supply, so balanced line voltage is needed for proper rectifier loading. Input fluctuations are permitted within a ±10 % tolerance, which covers normal utility variation and standby generator drift. Energy produced during rapid deceleration is routed externally because the unit is delivered without a built-in brake chopper; applications that need regenerative braking must use a separate resistor module. The unit uses the generation 1 design, which matches other first-generation RD frames for fit and layout. No optional technology functions are pre-installed, so the drive remains focused on standard variable-frequency motor control.