Product Description:

The RAC 2.3-250-380-A0I-Z1 spindle drive controller is produced by Bosch Rexroth Indramat and belongs to the RAC Spindle Drive Controllers series. As an AC main spindle drive controller, it converts three-phase mains power into regulated output for high-speed machining spindles and coordinates torque, acceleration, and deceleration commands issued by the machine CNC. Its integration in industrial automation allows accurate spindle speed regulation that supports metal cutting, grinding, and similar processes. Stable control during changing load conditions helps the spindle maintain the commanded speed while the machine moves through different cutting steps.

The controller is cooled by an internal blower, so heat from the power electronics is expelled without external ducting and the unit stays within its thermal limits at full load. It connects to plant power through a 3 × AC 400 V 50/60 Hz supply, which matches common industrial mains. At nominal load, the DC link current reaches 250 A, so upstream wiring and protection must be sized accordingly. Speed reference arrives as an analog ±10 V speed command, allowing direct connection to CNC controls that send a bipolar signal for acceleration and deceleration. Field wiring connects through an X4, 9-pole interface, which groups the control lines on one plug and keeps terminal access organized.

The unit is in series 2 and version 3. For dynamic braking, it includes an additional bleeder whose resistor dissipates regenerative energy during rapid deceleration and helps prevent DC bus overvoltage. An incremental encoder output mirrors spindle position for devices such as tool changers or monitoring circuits. The controller operates without an additional encoder input, so the standard spindle encoder remains the main feedback source for closed-loop control. This arrangement supports applications that need speed feedback sharing without adding a second auxiliary encoder channel.