Product Description:

The Bosch Rexroth Indramat RAC2.1-250-380-AP0-W1 is an AC main spindle drive controller from the RAC Spindle Drive Controllers series. Designed to regulate high-power machine-tool spindles, the unit converts three-phase energy into precise speed and torque commands that synchronize cutting, grinding, or boring operations with CNC instructions. By integrating current, voltage, and position loops inside one enclosure, the controller replaces discrete analog amplifiers and enables closed-loop spindle positioning for rapid axis indexing and rigid tapping. This layout supports accurate spindle control during speed changes, orientation moves, and other machining sequences that depend on repeatable response.

In normal operation, the controller connects directly to a mains supply of 3 × AC 400 V and can deliver a continuous phase current of 400 A to the spindle motor. Velocity commands are accepted as a differential speed setpoint of ±10 V, enabling straightforward interfacing with most CNC control cards. Internal electronics are powered by an auxiliary bus that draws 24 VDC at up to 1 A. This low-power circuit keeps the control logic active during mains outages so parameters and diagnostics remain accessible, and these values describe the electrical requirements for normal operation.

Thermal management relies on a built-in fan that moves at least 360 m³/h of cooling air against a back-pressure of 390 Pa, keeping the power stage within its specified temperature ceiling of +55 °C. The housing has a protection rating of IP 10, so it must be mounted inside a filtered cabinet. High-resolution feedback allows position commands to be executed in increments of 1/4,000,000 rev, supporting precise orient-spindle routines. With a mass of 121 kg, the controller is suited for fixed floor-standing cabinet installation up to 1000 m above sea level. The unit has no additional encoder input, bleeder, or interface, which keeps the connection layout straightforward.