Product Description:

The KDA 3.1-150-3-A0I-U1 spindle drive is produced by Bosch Rexroth Indramat for the KDA Spindle Drives series. This unit converts a common DC link into a controlled three-phase output for machine-tool spindles, allowing precise velocity and torque regulation in CNC machining centers, grinding systems, and automated production cells. By combining power conversion with closed-loop feedback, it maintains commanded speed during rapid load changes and supports consistent surface finish and tool life in industrial automation.

The power section is energized by 300 VDC from the shared supply, which provides the intermediate-circuit energy available to the inverter. From that bus, the drive can furnish up to 150 A of continuous phase current, giving large spindle motors the current needed for high-acceleration cutting cycles. Losses generated by the switching devices are removed by a mounted heat sink blower. Because airflow is actively forced, the cooling method is classified as forced cooling and keeps internal junction temperatures within design limits during sustained duty. The blower itself runs from a dedicated 115 V/50–60 Hz source, allowing ventilation to stay active during coast-down or maintenance when the DC link is de-energized.

On the control side, the unit offers an incremental encoder output so spindle position feedback can be wired directly to the numerical control. The speed reference is taken as an analog ±10 V signal, simplifying integration with standard motion cards. The unit can operate between 5 to 45 °C; outside this range, additional enclosure conditioning is required to avoid thermal derating. Installation altitude is limited to 1000 m above sea level, which helps maintain adequate air density for cooling and reliable insulation distances. A secondary encoder input is not provided, so applications that need dual feedback must implement that function at the control level.