Product Description:

The KDA 3.1-050-3-LQ0-U1 is a spindle drive manufactured by Bosch Rexroth Indramat for the KDA Spindle Drives series. It conditions DC bus energy and closed-loop commands so that a machine-tool spindle can accelerate, hold speed, and decelerate with repeatable accuracy. By converting numerical setpoints into precise phase currents, the unit serves as the link between the CNC controller and the high-speed induction or synchronous motor that performs the actual cutting or grinding work. This role allows the spindle system to respond smoothly to commanded speed changes during drilling, milling, and finishing operations.

This model belongs to design series 3 and operates from a common DC link that provides 300 VDC. It can deliver a continuous phase output of 50 A, which sets the steady-state torque range for the connected spindle motor. Velocity setpoints are received over the SERCOS interface, which gives the control loop fiber-optic immunity to electrical noise. A mounted heat sink blower is fixed on the rear panel to pull air through the fin stack. The blower uses an auxiliary supply of 115 V at 50–60 Hz, and the unit uses forced cooling to maintain semiconductor temperatures during rapid speed changes and high-duty machining cycles. Active airflow across the cooling surfaces helps the drive remain stable during repeated acceleration and speed-holding periods.

The drive is specified for ambient temperatures from 5 °C to 45 °C and will maintain its current rating up to 1000 m above sea level without derating. Cabinet wiring is simplified because the electronics bay offers no additional interface option. All communication relies on the optical command channel, while power conductors remain limited to the DC bus and motor terminals. The limited interface configuration keeps the connection layout focused on essential power and control functions. This arrangement reduces unnecessary wiring paths inside the cabinet and leaves the primary communication method clearly separated from the motor power circuit.