Product Description:

Bosch Rexroth Indramat manufactures the KDA 3.3-100-3-AP0-U1 as part of its KDA Spindle Drives series. The unit is a spindle drive that converts a fixed DC link into variable three-phase output for high-speed machining spindles, keeping rotational accuracy under closed-loop control. By integrating power electronics, cooling hardware, and feedback terminals in one housing, the device simplifies cabinet layout in automated milling, drilling, and grinding stations.

The internal power stage is supplied by 300 VDC; this constant link voltage comes from a separate converter and sets the energy ceiling for the drive’s transistors. A continuous output capability of 100 A indicates how much phase current can be delivered to the spindle without derating, supporting rapid acceleration under heavy cutting loads. Speed is commanded through an analog reference, so a ±10 V velocity signal from a CNC control can modulate spindle speed. A blower mounted on the heatsink is powered by 115 V at 50/60 Hz, so the cooling fan can operate independently of the DC bus. The electronics are specified for an ambient temperature range of 5 to 45 °C; remaining within this range helps prevent thermal shutdown and supports stable operation. Version 3 of the series also offers a second encoder socket that can accept spindle feedback or additional motor position data, allowing higher-order control loops without extra amplifier modules.

Heat removal relies on a mounted heatsink blower operating in forced cooling mode, which keeps semiconductor junctions below their design limits during sustained high current. Installation is permitted up to 1000 m above sea level; beyond that altitude, reduced air density lowers cooling performance and current ratings. Because there is no additional interface option, wiring is limited to power, encoder, and analog command connections.