Product Description:

The RD51.1-4B-018-L-C1-FW is a drive controller produced by Bosch Rexroth Indramat within the RD 500 Drive Controllers series. It is intended to regulate three-phase induction motors in automated production lines, conveyors, and processing machines where adjustable speed is needed during normal operation. By converting fixed mains power into variable-frequency and variable-voltage output, the unit lets the motor respond to changing load conditions without relying on mechanical gear changes. This supports smoother process adjustment when a machine must speed up, slow down, or hold a consistent operating point under varying demand.

The control method uses U/f curve control, so output voltage rises with frequency to maintain motor magnetization during acceleration and load changes. A built-in brake chopper handles regenerative energy during rapid deceleration and helps protect the DC link from overvoltage when rotating loads return energy to the drive. Thermal management uses forced air cooling, supporting continuous operation at a rated output of 18.5 kW. The power section accepts 380 to 480 V input, allowing the same controller to serve common industrial mains systems without requiring a different unit for each standard voltage range.

The supply configuration is a 3 x AC converter, which allows direct connection to a three-phase mains source. The unit is built in design generation 1, which identifies this release and its matching option card arrangement. The input side tolerates voltage variation of ±10 % around the nominal range, helping the controller remain stable during moderate line fluctuations. A separate 24 V standby power feed can keep communication functions active when the main power stage is switched off on converters rated up to 110 kW. This is useful when the control system must remain responsive during standby or a controlled shutdown.