Product Description:

The RAC 4.1-400-460-LP0-W1 is manufactured by Bosch Rexroth Indramat and belongs to the RAC Spindle Drive Controllers series. Classified as an AC main spindle drive controller, it forms the interface between the plant’s CNC system and the high-speed spindle motor, issuing regulated current and speed commands so machining processes maintain programmed feed rates and surface finishes. It is intended for spindle applications that require stable operation during changing load conditions and repeated speed changes. The controller supports the precise motor response needed for machining tasks such as drilling, milling, tapping, and threading.

For thermal management, the unit uses a built-in blower, which moves air across the power section during operation. Mains power is accepted through 3 × AC 400 V, 50 Hz, ±15% or 3 × AC 460 V, allowing installation on European or North American shop floors without a transformer. The power section can deliver a continuous output of 400 A, which supports large induction or synchronous spindle motors during rapid acceleration and steady cutting duty. An additional encoder input for spindle feedback gives the control loop another source of motion data, and command and diagnostic signals are routed through X4 optical waveguides, providing fiber links that resist electrical noise in machine cabinets.

Velocity references arrive over the deterministic SERCOS interface, so update cycles stay synchronized with axis drives on the same network. Rotor angle is resolved by a high-resolution INDRAMAT encoder, helping the controller maintain smooth vector control at low spindle speeds used for tapping or threading. Because the unit is supplied without an additional bleeder, regeneration energy must be handled by the connected braking resistor or shared DC bus. The unit is Version 1 within the 4.x controller generation, and this identifies it as the first release of that version line.