Product Description:

The RD51.2-4B-005-P-A2-FW is a drive controller manufactured by Bosch Rexroth Indramat for the RD 500 Drive Controllers series. Within an automation cell, it converts fixed mains power into variable-frequency output that regulates standard squirrel-cage motors used on conveyors, mixers, and pump skids. As part of the modular RD 500 platform, the unit serves as the central power stage between the plant supply and the motor windings while executing speed or torque commands from a programmable logic controller. This arrangement allows the motor to match process demand more smoothly than direct across-the-line operation.

It belongs to design generation 2 and uses U/f curve control, so motor voltage rises linearly with frequency to maintain magnetizing current when operating without feedback devices. The continuous output capability is 5.5 kW, and excess heat is moved into a heat dissipation panel rated for drives up to 18.5 kW, allowing cabinet mounting without forced ventilation. During rapid deceleration, regenerated energy is processed by the built-in brake chopper, which protects the DC link and supports controlled stopping with moderate inertia loads. EMC compliance at the cabinet door is simplified by an integrated mains filter that attenuates conducted noise on the supply conductors.

For mains connection, the controller is supplied as a 3 x AC converter that accepts phase-to-phase voltage from 380 to 480 V and tolerates line variation of ±10% without tripping. Its protective routine supports external standby power, allowing the control electronics to remain energized from a separate low-energy source while the main contactor is open. A dedicated starting lockout channel then blocks unintended drive enable until operating conditions have been verified. This helps keep the control section active for status handling even when the main power path is disconnected.