Product Description:

The KDA 3.1-050-3-DPI-U1 spindle drive is manufactured by Bosch Rexroth Indramat and belongs to the KDA Spindle Drives series. It is installed in multi-axis machining cabinets where it regulates three-phase power to high-speed spindle motors under digital control. Acting as the axis-specific inverter, the unit receives speed commands from the CNC, monitors motor feedback, and modulates current so the spindle can accelerate, decelerate, and maintain precise cutting speeds during milling, drilling, and grinding operations. That closed-loop control helps the spindle hold commanded speed as cutting load changes, which supports consistent machining quality. It is suited to machine tools that depend on fast speed changes between process steps.

The drive operates from a DC link of 300 VDC and can supply a continuous phase current of 50 A, enabling rapid torque delivery for demanding spindle acceleration. Thermal energy is removed by a heatsink-mounted blower, and its fan motor uses an auxiliary supply of 115 V at 50/60 Hz. This arrangement, together with forced cooling, helps keep internal temperatures stable when the unit is mounted beside other power modules. The controller receives its speed reference as a 16-bit parallel digital word, allowing the CNC to send exact speed values without relying on an analog reference signal.

The electronics operate in ambient temperatures from 5 °C to 45 °C, and no derating is required at elevations up to 1000 m above sea level. An incremental encoder output lets external position controllers track spindle angle, while a separate second encoder input can accept spindle or auxiliary motor feedback for different machine layouts. This added feedback path gives the drive more flexibility in machines that use separate spindle sensing or auxiliary motor feedback devices. The unit is part of Series 3 and is intended for continuous CNC operation where stable speed control and synchronized spindle feedback are required.