Product Description:

Bosch Rexroth Indramat builds the medium-frequency inverter PSI6200.000-W1 for the PSI Frequency Inverters series. The unit converts three-phase mains power into a regulated medium-frequency output that drives inductive heating coils and resistance-welding heads in automated stations. Control systems address the inverter through a 1 mA analog input and a 24 VDC weld-time signal, enabling precise adjustment of the energy delivered during each cycle. An IP20 housing allows the device to be mounted inside protected electrical cabinets, while feeder conductors up to 95 mm² can be terminated at the power blocks.

The power stage accepts a 400–480 VAC three-phase supply and delivers up to 1200 A of output current when peak loading is required. For continuous operation, the nominal system current is 220 A, and feedback monitoring in the gate drive is digitized with a current resolution of 0.1%, allowing tight regulation of welding energy. The inverter’s H-bridge switches operate at a sequence frequency of 1000 Hz, so the magnetic components can be smaller while still handling process dynamics. A downstream bus can experience secondary currents as high as 54 kA during short-circuit events, which is relevant when selecting protective devices. Basic cabinet dissipation is 69 W and rises to 210 W at maximum electrical power.

The inverter uses a water-cooled heat sink, so the control cabinet does not require large volumes of cooling air. A dedicated circuit must provide a coolant flow rate of 4 L/min through the M16 × 1.5 threaded connections. The coolant inlet temperature is limited to 30 °C to keep semiconductor junction temperatures within their operating limits. When the process runs at maximum duty, the cooling circuit must remove up to 700 W of thermal loss, with residual heat conducted directly to the baseplate. Operation is permitted in plant areas where the ambient air temperature does not exceed 55 °C, and the sealed liquid path helps keep dust away from sensitive power electronics.