Product Description:

The RAC 2.3-250-380-LP0-Z1 is an AC main spindle drive controller produced by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. It governs the torque and speed of high-speed machining spindles, linking the motion sequence of the machine tool to the numerical control. By combining a power section with an integrated control section, it supplies regulated three-phase power to induction or synchronous spindle motors used in milling, turning, and grinding centers. It is intended for machine tools that need accurate spindle response during both constant-speed cutting and rapid speed changes.

This controller operates from a nominal supply of 3 x AC 400 V at 50 to 60 Hz and can deliver a continuous output of 250 A to the spindle inverter section. Speed commands arrive over the SERCOS interface, so real-time setpoints can be exchanged with the CNC over the optical drive network. Thermal energy produced under sustained load is removed by an internal blower, and an additional bleeder absorbs regenerated energy during rapid deceleration to help prevent DC-link overvoltage. The unit is in hardware release 2, and the control software is in release family 3.

Communication and diagnostic data are routed through the X4 optical waveguides, which support noise-resistant exchange with the supervisory control. Position and velocity regulation use a high-resolution INDRAMAT encoder mounted on the spindle, and an additional encoder input is available when a secondary feedback device is needed for dual-loop control. These feedback paths help the drive maintain stable spindle behavior during surface finishing and other high-speed processes where small speed errors can affect results. The unit is identified as Version 3, and that version contains parameter blocks for the optical master, the built-in protection functions, and coordination of braking energy with the extra bleeder resistor bank.