Product Description:

The KDA 3.3-150-3-API-W1 belongs to the KDA Spindle Drives series from Bosch Rexroth Indramat. As a spindle drive, it supplies controlled three-phase power to high-speed machine-tool spindles. It synchronizes speed commands with encoder feedback so that cutting, drilling, or grinding processes maintain precise surface speeds and repeatable cycle times within automated production lines.

This unit is powered internally from a DC bus of 300 VDC; that voltage feeds the IGBT bridge that generates variable-frequency output for the spindle motor. A continuous output capability of 150 A allows the drive to handle large acceleration torque without derating during prolonged machining cuts. Thermal limits are managed by a mounted heat sink blower, and airflow is directed across the aluminum fins to remove semiconductor heat. Because the unit uses forced cooling, the cabinet must maintain an unobstructed exhaust path rather than rely on natural convection. Acceptable ambient conditions are between 5 to 45 °C, so operation outside this range can shorten component life or trigger temperature alarms that inhibit spindle motion.

The blower itself is supplied from an auxiliary line of 220 V/50-60 Hz, separating fan power from the DC link so the cooling circuit remains active during regenerative or standby states. Installation is permitted at elevations up to 1000 m; above that level, thinner air can reduce cooling efficiency and may require current derating. For position and speed monitoring, the front panel carries an incremental encoder output that mirrors the incoming spindle feedback signal to CNC controllers or oscilloscope ports, while a second encoder socket supports auxiliary motor feedback when multi-channel monitoring is needed. The velocity loop accepts an analog speed command value, enabling direct ±10 V reference signals from legacy numerical controls without additional fieldbus hardware.