Product Description:

The RAC 3.5-200-460-A0I-W1-220 is an AC main spindle drive controller produced by Bosch Rexroth Indramat for the RAC Spindle Drive Controllers series. It forms the core power interface between factory mains and the asynchronous or synchronous spindle motor on high-speed machining centers. By modulating current, voltage, and frequency in real time, the controller delivers the commanded torque and speed profile needed for drilling, milling, or grinding cycles. A compact design integrates the control electronics and power stage, which simplifies panel layout and allows the unit to be wired directly to CNC or PLC hardware that issues an analog velocity reference.

The power section is rated for a continuous output of 200 A, giving ample headroom for rapid acceleration of large-inertia spindles. Mains can be supplied at 3 x AC 400 V, and the device tolerates line variations of ±15% without derating, so it remains stable on weak or fluctuating utility feeds. Thermal management is handled by an internal blower, eliminating the need for external heat sinks or ducting. The velocity loop accepts an analog (±10 V) speed command, a format widely used on both legacy and newer CNC systems. The unit does not use an additional bleeder resistor, and no secondary encoder input is provided, so feedback handling remains focused on the primary spindle encoder.

For installations using higher mains, the controller also accepts 3 x AC 460 V supplies. Its control electronics draw from an isolated AC 230 V / 50/60 Hz service feed, and field wiring for I/O and low-level signals is arranged on the X4 9-pole terminal block. Version 5, Series 3 hardware provides an incremental encoder output for downstream monitoring devices such as spindle orientation modules or external tachometers, allowing actual speed to be verified without loading the primary feedback channel.