Product Description:

The KDA 2.1-050-3-AY0-U1 spindle drive is produced by Bosch Rexroth Indramat as part of the KDA Spindle Drives series. This unit is engineered to close the speed loop on high-performance machine-tool spindles, receiving command data from a CNC controller and delivering controlled three-phase power to the attached motor. By stabilizing rotational velocity under variable cutting loads, the drive supports precise surface finish and tool life targets in automated machining lines, and it mounts inside the electrical cabinet where it shares a common DC bus with other axis modules.

Inside the cabinet, the drive draws a continuous output of 50 A, a current capacity sized to accelerate large spindle inertias without oversaturating the stator windings. Its DC link of 300 VDC couples to a shared power supply, allowing energy exchange among multiple axes during deceleration and regeneration. Thermal management relies on a mounted heat sink blower for forced cooling; the blower itself is fed from a separate 115 V/50-60 Hz single-phase source so spindle load changes do not affect airflow. Safe operation is specified for ambient temperatures between 5 to 45 °C, and above this range the unit must be derated to prevent semiconductor overheating. Field wiring is limited to the standard control terminals provided by the base design.

Installation limits include a ceiling of 1000 m above sea level, beyond which reduced air density lowers the blower’s cooling effectiveness. The speed reference reaches the control board as an analog voltage, allowing straightforward integration with legacy CNC hardware that lacks high-speed fieldbus channels. For feedback, a Second encoder input can be wired in parallel with the motor’s primary sensor to synchronize spindle position with an external axis or probe. Within the KDA architecture, the unit is identified as Series 2, placing it in the second design generation of this spindle drive platform.