Product Description:

The PSI65C0.766-W1 is a medium-frequency inverter produced by Bosch Rexroth Indramat within the PSI Frequency Inverters series. The unit converts three-phase mains power into controlled welding current for robotic cells and automated resistance welding guns. By modulating output at the sequence standard of 1000 Hz, it supplies stable energy to transformer electrodes while the timer hardware coordinates squeeze, weld, and hold phases in high-throughput manufacturing lines.

The inverter accepts a supply range of 400 - 480 VAC, delivered through mains and transformer cables that can each reach 2x120 mm². With water cooling active, the unit sustains a nominal output of 660 A, and it can provide peaks up to 2400 A when thicker materials require higher weld current. The internal power stage can dissipate 4400 W of cooling losses without derating. The unit stores thirty-two stepper programs in nonvolatile memory, and each program can include five steps for tailored weld profiles. A minimum pre-weld or squeeze interval of 16 ms is used to seat the electrodes before current flow begins. Real-time coordination is handled through an EtherNet/IP interface and an Ethernet timer, while the stop circuit is rated for 24 VDC at 3 A for connection to safety relays.

The cooling circuit is water based. Baseline cabinet dissipation is 100 W, and this value rises to 850 W when the inverter operates at maximum duty, so enclosure airflow must be managed accordingly. At least 10 l/min of coolant is required, and the resulting pressure drop is 0.65 bar at 10 l/min, which matches common plant chiller capability. The heat exchanger must absorb residual cabinet losses while the main water jacket removes heat from the semiconductor modules. The 24 V stop circuit remains isolated from the power section, and the stored weld sequences help maintain consistent current delivery across repeated welding cycles.