Product Description:

The KDA 3.1-150-3-LP0-U1 is a spindle drive produced by Bosch Rexroth Indramat and assigned to the KDA Spindle Drives series. As a closed-loop power module, it converts the direct-current link of an Indramat supply unit into precisely regulated three-phase power for machine tool spindles. Within an automation cell, it maintains commanded speed profiles, manages acceleration currents, and supplies diagnostic data to the motion controller, allowing consistent surface finish and tool life in high-speed machining applications.

The drive is fed from a DC bus at 300 VDC, so the upstream supply module can regenerate energy during spindle deceleration. Its output stage is rated for 150 A continuous current, giving the connected motor short settling times during rapid tapping, boring, or grinding cycles. Cooling is handled by a mounted heat sink blower that pulls ambient air across the power semiconductors; the blower operates from an auxiliary source of 115 V/50–60 Hz, keeping the main DC path isolated. Speed commands arrive digitally over the SERCOS interface, which transmits setpoints and status through real-time fiber loops. A second encoder input is available so the controller can read spindle-mounted feedback or an auxiliary motor encoder, improving position accuracy at low speed. The unit has no additional interface option, which reduces cabinet wiring inside multi-axis machining centers.

Installation requires attention to thermal and altitude limits. The unit can be mounted where ambient air stays within 5 to 45 °C; within this range, the power transistors and gate drivers remain within their intended operating temperatures. Operation is permitted up to 1000 m above sea level without current derating. Cooling uses forced air, so sufficient clearance must be provided around the fan inlet and outlet to prevent recirculation. The unit is in Series 3.