Product Description:

The RAC 2.2-250-380-D0I-W1 is an AC main spindle drive controller produced by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. Within the series, it is classified as device type 2 and version 2. Installed between the plant's three-phase supply and a machine tool spindle motor, the unit converts mains power and issues digital speed references so the spindle can hold commanded speed under changing load. This operating role suits machine tools that require stable spindle speed during cutting, drilling, or tapping cycles. It also integrates with other Indramat modules through the dedicated X4 command connector on the front panel.

The rated connection is 3 x AC 400 V at 50–60 Hz, allowing direct wiring to standard industrial distribution systems. Under continuous duty, the power stage supplies up to 250 A, giving enough headroom for high-inertia spindle acceleration without current clipping. Heat is removed by an internal blower, and the built-in fan moves air across the heat sink so the controller can operate in a sealed cabinet. Motion references arrive as a 16-bit parallel digital word, enabling the CNC to command spindle speed with a resolution of 1 part in 65,536 while avoiding analog noise.

An integrated 25-pole X4 terminal carries power-on signals, diagnostics, and encoder lines. The drive is supplied without an additional bleeder, so excess regenerative energy must be handled by an external resistor when the application requires extended braking. It is also delivered without an additional encoder input, so spindle position is monitored through the primary channel only. A factory-installed incremental encoder output reproduces quadrature A, B, and index signals for synchronizing auxiliary axes during tool orientation or rigid tapping. This output supports coordinated motion functions that depend on shared position and speed signals.