Product Description:

The KDA 3.3-150-3-AP0-U1 is a spindle drive produced by Bosch Rexroth Indramat as part of the KDA Spindle Drives series. Designed for machine tools, it converts DC link energy from an Indramat power supply into controlled three-phase output for high-speed spindles. In a machining cell, the unit acts as the interface between the CNC or PLC and the spindle motor, coordinating torque, speed, and position under closed-loop control. The drive is intended for closed-loop spindle regulation where commanded speed must remain stable despite changing load conditions. It is commonly used where the spindle must respond quickly to CNC commands during drilling, milling, or similar machining operations.

Electrically, the drive is supplied from a bus at 300 VDC and can continuously deliver up to 150 A of armature current, supporting demanding cutting loads. Continuous current capability helps the drive sustain torque during longer cuts instead of only during short peaks. Thermal energy is removed by a mounted heat sink blower that uses forced cooling. Air is pulled through the fin stack by a motor energized from a separate line rated at 115 V/50-60 Hz. A second encoder input lets the control read spindle position or an auxiliary motor feedback channel, which improves synchronization in multi-axis applications. The unit is part of the third release in the series.

The ambient operating window spans 5 to 45 °C, and reliable function is maintained at elevations up to 1000 m above sea level before derating is required. Speed reference information reaches the regulator as an analog command voltage, allowing direct connection to legacy CNC boards. This analog input is useful in retrofit systems that still use voltage-based spindle commands rather than digital communication. The unit has no additional interface option, so the connection layout remains limited to the standard ports. This fixed interface arrangement keeps the control scheme straightforward for systems that do not require expansion cards.