Product Description:

The PSI63C0.120-L1 medium-frequency inverter is produced by Bosch Rexroth Indramat within the PSI Frequency Inverters series. The design follows the company’s medium-frequency welding architecture for resistance welding applications. It converts three-phase mains power into a controlled medium-frequency output for welding equipment. In automated lines, the unit delivers accurately timed energy to workpiece electrodes while exchanging discrete control signals with cell-level PLCs and safety interlocks.

The inverter accepts a three-phase supply of 400 - 480 VAC and uses air cooling. Control integration is handled through 26 discrete inputs that receive weld enable, schedule select, and reset commands, while 19 discrete outputs return ready or fault indications to the surrounding machine controls. Four auxiliary inputs are provided for secondary triggers, and the E/A_DISKR2ED module maps these lines to field terminals. Eight program-select bits allow quick switching between stored parameter sets, and the power stage modulates at a standard cycle rate of 1000 Hz. Safety timers are built in; if the main contactor does not close within 200 ms, the inverter disables firing, and the potential-free stop circuit can interrupt a 24 VDC, 3 A loop when an emergency stop request is present.

For heavy production cells, the unit can drive up to 32 electrodes, and a watchdog halts operation when feedback is absent after 250 ms. The weld circuit may stay energized for as long as 60 s to meet hold requirements on thick material and similar high-thermal-mass joints. Power wiring is simplified because the mains connector supports conductors up to 50 mm², and the transformer side uses the same cross-section. One auxiliary output can actuate a 24 V timer relay, and the internal timer operates on the same voltage. The unit does not issue predefined general status codes, so supervisory controllers can interpret the discrete feedback according to plant-specific schemes.