Product Description:

The RAC 3.5-150-460-LP0-W1-220 is an AC main spindle drive controller developed by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. Intended for CNC machining centers and other automated tooling stations, the unit converts three-phase mains power into regulated spindle current and provides speed references through a digital bus. Acting as the central power stage in a closed-loop spindle axis, it manages motor torque, processes encoder feedback, and exchanges operating data with the machine control. That control role is important in machining applications where spindle speed must stay stable under changing load conditions during drilling, milling, and tapping cycles.

A rated connection voltage of 3 x AC 400 V, 50 Hz, ±15% or 3 x AC 460 V allows the controller to operate on common plant supplies without a transformer. The control electronics are fed separately with AC 230 V / 50-60 Hz, which keeps the logic supply independent from the main power stage. At full load, the inverter can deliver 150 A for large-frame spindle motors during acceleration and heavy cutting. Thermal energy is removed by a built-in fan, so the unit does not require external cabinet airflow. Velocity commands arrive over the SERCOS interface, allowing deterministic fiber-optic communication with the CNC and supporting standard drive data exchange.

Feedback enters through the X4 optical waveguide connection, which uses the same glass-fiber medium as the command channel to help reduce electrical noise. Precise rotor position data are supplied by a high-resolution Indramat encoder connected through an additional encoder input for spindle feedback, giving stable speed control at low rpm and reliable phase alignment during tool changes. Using optical communication for feedback also helps maintain signal quality in cabinets with high switching noise from the spindle power section. The unit is supplied without an additional bleeder, so regenerated energy must be handled by the connected spindle motor or by an external brake resistor. It is a Series 3, Version 5 model, and the type code includes LP0 and W1 designations.