Product Description:

The RAC 2.3-250-380-LP0-W1 is an AC main spindle drive controller produced by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. Installed between the CNC control and a high-speed spindle motor, it modulates three-phase power to manage torque and surface speed during metal-cutting, grinding, or wood-routing operations. It regulates spindle behavior during acceleration, steady cutting, and deceleration so machining cycles remain stable under changing load conditions. By combining closed-loop current regulation with high-bandwidth command processing, the unit supplies the dynamic response required for precision machining while remaining electrically compatible with standard European utility grids.

The power section is designed for a line supply of 3 x AC 400 V, 50-60 Hz, so it can be wired directly to common factory mains without an isolation transformer. Under continuous duty, it delivers a rated output of 250 A, letting it accelerate large-diameter spindles without oversizing the cabinet inverter. Velocity setpoints reach the controller through a SERCOS interface, which carries speed commands, status data, and diagnostics over fiber-optic cable to reduce electrical noise in the control path. For backplane wiring, the control board offers a dedicated X4 optical-waveguide connection that supports optical communication inside multi-axis racks. Thermal management relies on a built-in internal blower that channels air across the IGBT heat sink, eliminating the need for external ducting in most cabinets and helping maintain stable operation during sustained spindle demand.

Motion feedback accuracy is enhanced by a high-resolution Indramat encoder that provides fine incremental counts per revolution and supports precise speed regulation at the spindle. When machines require dual monitoring, an additional encoder input for spindle feedback can be activated to cross-check speed and angular position during synchronized processes. Energy return paths are simplified because the unit is supplied without an additional bleeder, so regenerated power is handled by the common DC bus or a drive-line chopper. The controller is Version 3 and uses the series-specific parameter structure for this drive platform.