Product Description:

The PSI61C0.765-L1 is a medium-frequency inverter produced by Bosch Rexroth Indramat within the PSI Frequency Inverters series. It converts three-phase factory mains into controlled medium-frequency power for resistance welding heads, induction heaters, and similar automated loads. The inverter supplies the process current required by connected equipment, while a separate logic circuit supports supervisory electronics. Its onboard controls manage current delivery, stored process programs, and communication with higher-level control systems.

The inverter accepts a supply of 400–480 VAC and can draw up to 110 A from the line. This input range supports operation on standard plant power, while the available current accommodates large transformer primaries. Control electronics operate from a separate 24 VDC logic supply and consume 1.5 A, leaving capacity within the 2 A auxiliary power supply for sensors. Forced-air cooling removes heat without requiring liquid cooling lines inside the cabinet. The TriCore CPU can execute up to 256 stored programs, and Ethernet I/O with an Ethernet timer structure exchanges setpoints and status data with PLCs. Conductors connected to the mains bus must have a cross-sectional area of at least 35 mm² to manage resistive heating. The enclosure has an IP20 rating and must be installed in a protected electrical cabinet. With a mass of 20 kg, the inverter places a moderate mechanical load on the mounting panel.

On the secondary side, the converter can energize as many as 32 welding electrodes. It delivers a maximum primary current of 400 A, which is transformed into an output of up to 20 kA at the workpiece. Output current is modulated at 1 kHz, helping reduce transformer core losses while maintaining precise control over heat input. Steady-state cabinet dissipation is limited to 69 W, allowing the forced-air system to manage the thermal load without an internal liquid circuit. The combination of stored programs and Ethernet communication allows process commands, timing data, and operating status to be exchanged with the connected control system. High secondary current supports resistance welding processes that require concentrated heat at the electrode contact point.