Product Description:

The RAC 3.5-150-460-API-Z1-220 is an AC main spindle drive controller produced by Bosch Rexroth Indramat within the RAC Spindle Drive Controllers series. Designed for machine tools and production lines, it converts three-phase mains power into regulated spindle power while accepting speed commands from the CNC. The unit forms the link between motion control electronics and the high-speed spindle motor, providing closed-loop regulation of torque and velocity during metal-cutting or grinding operations where stable spindle speed supports process accuracy.

The power section is fed by 3 x AC 400 V, 50 Hz, ±15% or 3 x AC 460 V. This dual-range input lets a plant run the same controller on European or North American mains without tap changes, which supports use across facilities with different supply standards. A continuous output capability of 150 A supplies the large current pulses demanded by rapid acceleration and deceleration of heavy spindles. Thermal energy from switching components is removed by a built-in fan, so no external ducting is required for cabinet cooling. Control electronics draw their auxiliary supply from AC 230 V / 50-60 Hz. Spindle velocity is adjusted through an analog (±10 V) speed reference, allowing real-time command signals from legacy or modern CNC boards during speed changes and synchronized spindle functions.

Position control accuracy is enhanced by a high-resolution INDRAMAT encoder channel, and the unit also includes an additional bleeder resistor to dissipate regenerated energy during rapid spindle stops. Field wiring is landed on the X4 9-pole terminal strip, simplifying encoder and I/O connections while keeping interface points grouped in one location. An incremental encoder output mirrors spindle position for external monitoring devices and related control functions, and the additional encoder input supports advanced diagnostics and tuning functions without changing the controller's main power path.