Product Description:

The PSI65C0.730-W1 is a medium-frequency inverter produced by Bosch Rexroth Indramat for the PSI Frequency Inverters series. In resistance-welding cells and other automated joining stations, the unit converts three-phase mains power into a regulated medium-frequency output that the transformer applies to the electrodes. This arrangement reduces weld spatter, improves weld nugget consistency, and lowers transformer mass compared with line-frequency systems. The inverter supports automated welding processes that require accurate control of current timing and output intensity. Its regulated power conversion also helps maintain consistent results when operating conditions or material characteristics vary.

The inverter accepts a supply of 400–480 VAC at 50 or 60 Hz. Its power stage can draw up to 2400 A on the primary side, while a matching PSG 3100 transformer can supply as much as 120 kA on the secondary side. Pulse-width modulation operates at 1 kHz to balance switching losses and current ripple. A TriCore CPU executes 256 resident programs and coordinates three programmable weld times, while an EtherNet timer interface exchanges sequence data with the cell controller. The integrated 24 V supply provides up to 2 A for sensors and contactors. Internal heat generation is 100 W under a basic load and rises to 850 W when the current duty cycle reaches its maximum limit. The thermal circuit must remove maximum cooling losses of 420 W.

The power electronics use water cooling, and a minimum flow of 10 L/min through the M16 × 1.5 fittings keeps the substrate within its operating temperature limit. The cooling circuit produces a pressure drop of only 0.65 bar at that flow rate. Cabinet protection is rated at IP20, which protects against contact with hazardous internal parts and the entry of larger solid objects. The climatic classification is 3K3 under EN 60721-3-3, allowing operation from +10 °C to +55 °C. Storage is permitted between -25 °C and +70 °C when the inverter is not operating. The unit has a mass of 25 kg, which must be considered when selecting the mounting surface and cabinet supports. An onboard auxiliary bus distributes power to connected external relays used by the welding system.