Product Description:

The KDA 3.1-050-3-AQS-U1 is a spindle drive produced by Bosch Rexroth Indramat as part of the KDA Spindle Drives series. It regulates high-speed machine-tool spindles by converting a regulated DC link into three-phase output, while a heatsink blower removes thermal energy from the power section. The unit connects to higher-level CNC or PLC systems and uses an analog speed reference so the controller can vary spindle speed continuously during cutting or drilling cycles. This operating method supports smooth speed changes during acceleration, material engagement, and deceleration at the end of a machining sequence.

The power stage is energized from a 300 VDC intermediate circuit, and the output current is rated at 50 A, allowing the connected spindle to accelerate quickly under load. Thermal management relies on a blower powered by 115 V/50–60 Hz mains, so fan operation remains independent of the DC bus during normal use. Control and diagnostic data are exchanged through a RS-232-C serial interface, allowing access to parameter settings and fault information without adding a separate fieldbus link. Air is drawn across the external heatsink by forced cooling, which helps keep semiconductor temperatures within a safe operating range during sustained spindle duty.

The drive is intended for continuous operation between 5 to 45 °C, so it should be installed where cabinet temperatures stay within that range. Installation height is limited to 1000 m above sea level, because lower air density can reduce blower performance and heat dissipation. The speed reference is an analog voltage or current signal, which the internal regulator converts into torque-producing pulses for the motor. The unit is Series 3, indicating the product revision used for this model.