Product Description:

The RAC 3.5-200-460-API-W1-220 is produced by Bosch Rexroth Indramat within the RAC Spindle Drive Controllers series. Classified as an AC main spindle drive controller, it regulates motor torque and speed for machine-tool spindles used in milling, turning, and grinding centers. By combining analog speed commands with high-resolution feedback, the unit closes the loop between the CNC or PLC and the spindle motor, allowing repeatable acceleration and positioning across demanding duty cycles. This closed-loop operation helps the spindle respond predictably during speed changes, tool engagement, and commanded stopping sequences.

This controller draws a continuous output current of 200 A and is powered from a three-phase supply of 3 × AC 460 V. Internal logic and signal conditioning circuits operate on a separate feed of AC 230 V / 50–60 Hz, which helps keep the control electronics isolated from disturbances on the load side. The velocity reference arrives as an industrial standard ±10 V signal, noted as analog (+/-10 V), so the drive can follow proportional commands from most numerical controls. Thermal management is handled by an internal blower that moves cooling air through the housing without external ductwork. Field wiring lands on terminal X4, 9-pole, which groups enable, ready, and fault signals with the speed input for a simpler panel layout. This arrangement keeps control connections organized while separating command functions from the main power path.

Feedback versatility is ensured through an additional encoder input for spindle feedback, while position information can be retransmitted over an incremental encoder output for downstream synchronizing axes. Rotor position is interpreted with a high-resolution INDRAMAT encoder, providing fine phase detection at every electrical cycle. This allows the controller to process spindle motion data accurately during rapid speed changes and synchronized machine movements. The design omits an additional bleeder resistor and relies on the drive’s internal power section to manage regenerative energy during deceleration. The unit is Version 5, and the hardware is series 3.