Product Description:

The PSI63C0.761-L2 is a medium-frequency inverter manufactured by Bosch Rexroth Indramat as part of the PSI Frequency Inverters series. The unit converts high-voltage AC into regulated DC pulses that feed a welding transformer, making it the core power stage in automated resistance-welding lines, body-in-white fixtures, and similar fabrication cells. By modulating energy at a fixed switching rate, the inverter lets plant controllers deliver consistent heat input and very short weld cycles while limiting mains distortion.

It operates from a three-phase supply of 480–690 VAC and relies on a separate 24 V DC control rail for its internal logic and I/O. At the heart of the power stage, a carrier frequency of 1 kHz sets the pulse-width-modulated output that reaches a continuous limit of 800 A and a nominal system current of 110 A. Air cooling removes heat from the power semiconductors so full current can be delivered without liquid circuits. Interface capacity is large, with 208 serial inputs and 176 serial outputs processed by an EtherNet timer section, enabling the drive to exchange weld schedules and diagnostic bits with a supervisory PLC. Conductors can be landed on terminals up to 50 mm², while control wiring can be connected in sizes up to 35 mm². The electronics meet Humidity Class F to resist condensation in humid body shops.

For high-speed spot guns, the secondary circuit withstands peaks of 36 kA, and the shortest selectable pre-weld interval is 16 ms, allowing precise adjustment of squeeze, weld, and hold times. A built-in stop circuit carries 3 A to drop output safely on fault commands. Protection is rated at IP20, which is suitable for cabinet mounting up to a maximum installation altitude of 2000 m without derating. The inverter supports 32 electrodes per channel and accepts the clock-synchronized EtherNet timer for coordinated welding control.