Product Description:

The KDA 2.1-050-3-AQD-U1 is a spindle drive manufactured by Bosch Rexroth Indramat and assigned to the KDA Spindle Drives series. As a dedicated spindle controller, it converts a fixed DC link into a variable three-phase output that matches the torque and speed requirements of machine tool spindles, allowing closed-loop acceleration, deceleration, and position holding in automated machining centers. It acts as the interface between a shared supply module and the high-frequency windings of the spindle motor in turning, milling, or grinding equipment, where stable control is needed during both cutting and speed changes. This arrangement lets the controller regulate spindle speed during ramp-up, steady operation, and controlled braking.

The drive is energized from a DC bus of 300 VDC, so cabinet designs must provide a stable intermediate circuit at that potential. Its output stage is rated for 50 A continuous current, giving it sufficient headroom for rapid spindle acceleration and sustained load without an immediate thermal trip. To keep the internal heat sink blower active independent of the DC link, the unit requires an auxiliary source of 115 V/50-60 Hz. Speed reference is supplied as an analog voltage, while stepwise positioning commands arrive over a separate digital position command value interface; this separation lets a CNC issue velocity and indexing data at the same time without signal interference. The separated command paths also allow continuous speed demand and discrete positioning tasks to be processed without combining both signals on one channel.

Thermal management relies on a mounted heat sink blower that forces air through the fins attached to the power semiconductors. The drive is Series 2, and the forced-air path helps keep internal components within their permitted temperature range during operation. The unit can be installed where ambient air is between 5 to 45 °C, and it can operate up to 1000 m above sea level before derating is required. These installation limits are relevant in enclosed machine cabinets where spindle drives often run for long periods at changing loads.