Product Description:

The KDA 3.1-050-3-L0D-U1 is a spindle-drive unit manufactured by Bosch Rexroth Indramat as part of the KDA Spindle Drives series. In an automation cell, it sits between the cabinet DC bus and the motor, converting bus power into regulated three-phase output while exchanging real-time commands with the machine controller. Its primary role is to provide precise rotational speed and torque regulation for high-speed spindles used in milling, drilling, or grinding applications, and it supports consistent spindle response during changing process loads.

The power stage operates from a bus of 300 VDC and supplies up to 50 A of continuous motor current, so the matching spindle and supply must be sized accordingly. Heat is removed by a mounted heat sink blower as part of a forced cooling arrangement, and steady airflow helps keep the power electronics within their intended temperature range during heavy acceleration cycles. The blower is powered by a separate 115 V/50–60 Hz auxiliary line, which must be routed independently from the DC link connections. Speed references are transmitted over the optical SERCOS interface, giving deterministic command transfer and supporting synchronized operation with other controlled axes on the machine.

The unit is intended for operation in ambient air from 5 to 45 °C, which suits most enclosed electrical cabinets with normal ventilation. Installation altitude is limited to 1000 m before derating is required because lower air density reduces cooling effectiveness. For applications that require coordinated spindle positioning, a digital position command value channel is available to support commanded position changes in addition to speed control. The drive does not rely on a secondary encoder input for that function, which helps keep the control arrangement direct and easy to integrate.