Product Description:

The RD51.2-5B-018-L-A2-FW is a drive controller produced by Bosch Rexroth Indramat within the RD 500 Drive Controllers series. It is intended to modulate three-phase induction motors in automated machinery. By supplying variable-frequency power, the unit lets motor speed track process requirements while maintaining stable torque during routine operation. This operating method suits equipment that benefits from controlled acceleration, adjustable running speed, and smoother response than fixed-frequency motor supply can provide.

A built-in brake chopper dissipates excess DC-bus energy during rapid deceleration, allowing the unit to stop connected motors without external braking hardware. Speed regulation follows U/f curve control, so the voltage delivered to the motor changes in proportion to output frequency and preserves the magnetizing flux needed for steady low-speed torque. Thermal management relies on forced air cooling, and an integral fan moves ambient air across the heat sink to keep semiconductor temperatures within a safe range. The controller is design generation 2, which matches the later RD 500 connection layout and parameter set. The inverter’s continuous output rating is 18.5 kW, which is the nominal motor power it can support under standard line conditions.

The unit uses a 3 × AC converter input arrangement, so it rectifies and inverts a three-phase line supply without requiring a separate DC source. The permissible input window is centered on 500 V, matching common industrial power systems. For reduced energy use during idle periods, external standby power allows the control electronics to remain active while the main converter section stays off. Safety interlocks include a starting lockout that prevents unintended motor energization after power is restored. The controller is supplied without installed firmware, so the software package can be matched to the required motor data and communication options.