Product Description:

The KDA 2.1-100-3-LQD-U1 is a spindle drive module manufactured by Bosch Rexroth Indramat within the KDA Spindle Drives series. Designed for controlling high-speed machine-tool spindles, the unit converts regulated DC bus power into three-phase motor output while exchanging velocity and position data with a CNC or PLC over fiber-optic SERCOS. Its function in automation is to deliver precise speed and torque control for milling, drilling, and grinding axes that demand rapid acceleration and steady rpm. This type of closed-loop control helps the spindle maintain stable rotation during cutting operations that place changing loads on the motor.

The drive supplies up to 100 A continuously from its inverter stage, allowing it to energize medium-to-large spindle motors without derating. It is powered by a shared DC bus set at 300 VDC, so it is normally mounted beside a supply module in multi-axis cabinets. Heat sink airflow is produced by a blower that operates on 115 V/50-60 Hz; this fan forces air across the fins under forced cooling conditions to help prevent thermal shutdown during long machining cycles. The assembly is delivered with a mounted heat sink blower, which can be replaced from the rear of the unit if service is required. Speed setpoints are transferred through the fiber-optic SERCOS interface, enabling deterministic timing and integrated diagnostics between the drive and the motion controller.

Reliable operation is maintained in ambient temperatures from 5 to 45 °C, so the module can share an enclosure with control electronics in most factory climates. Installation is permitted up to 1000 m above sea level; above this height, additional derating may be necessary because reduced air density lowers cooling effectiveness around the heat sink. For applications that need direct spindle orientation or threading commands, a dedicated channel for a position command value is provided, supplementing the speed loop without extra interface hardware. This added command path supports positioning tasks that require the spindle to stop at a known angular location before the next machine cycle begins.