Product Description:

Bosch Rexroth Indramat produces the PSI63C0.733-W2 medium-frequency inverter within the PSI Frequency Inverters series. This unit converts high-voltage three-phase mains power into regulated medium-frequency output suited for resistance-welding installations and similar automation cells. By modulating current through multiple transformer taps, the inverter lets a control system deliver precise heat to each electrode, enabling repeatable seam or spot quality on automated production lines.

The input section accepts three-phase lines from industrial services rated at 480–690 VAC, and a nominal mains draw of 110 A sets the wiring, fusing, and contactor selection for the installation. Inside the inverter, a bus and switching stage can supply up to 800 A of primary current to the welding transformer; on the secondary of a PSG 3100 head this corresponds to a peak of 36 kA, supporting large cross-section workpieces. Continuous power dissipation in the enclosure is limited to 100 W, so most of the heat is shifted to the liquid loop rather than the air inside the panel, keeping ambient temperatures close to rated values.

A low-power logic stage with a TriCore processor supervises timing through the EtherNet timer and communicates with PLCs over an Ethernet interface. Auxiliary equipment can be powered from the internal supply, which provides 24 VDC at up to 2 A, removing the need for a separate control transformer in many cells. Thermal management relies on a water-cooled plate; operation requires a minimum coolant flow of 4 l/min, a maximum pressure of 10 bar, and typically shows only a 0.1 bar drop across the channels. The housing carries an IP20 rating, so the module is installed behind a protective panel. Cabinet loss at maximum welding duty is 140 W, and the controller can address up to 32 electrodes independently.