Product Description:

The KDA 3.1-050-3-API-U1 is a three-phase power module from Bosch Rexroth Indramat that belongs to the KDA Spindle Drives series. Deployed between the DC bus of an Indramat supply unit and a high-speed induction or synchronous spindle motor, the converter modulates output voltage and current so computer numerical control systems can execute drilling, milling, or grinding routines with controlled acceleration and braking. Integrated signal channels accommodate primary and auxiliary encoder data, letting the amplifier close a velocity and position loop without adding external interface cards.

The drive delivers up to 50 A of continuous output, drawing energy from a shared bus stabilized at 300 VDC. Internal housekeeping and logic rails remain unaffected because the heat sink blower is powered separately by a 115 V/50-60 Hz service line. A finned aluminum radiator with a mounted heat sink blower operates under forced cooling, sustaining airflow even when cabinet convection is poor. This hardware pairing allows the transistor bridge to dissipate switching losses quickly, preventing thermal foldback during low-speed spindle cutting, repeated tapping cycles, or prolonged dwell conditions common in automated machining cells.

The amplifier operates between 5 to 45 °C and at elevations up to 1000 m above sea level without output derating. For motion feedback, an incremental encoder output retransmits spindle position to the master control, while the secondary encoder socket accepts resolver or TTL signals so a work-holding axis can be supervised by the same unit. Speed commands arrive as an analog reference, simplifying retrofit work where legacy CNC hardware still issues ±10 V setpoints. The available feedback connections also support machines that combine spindle control with an additional monitored axis.