The VW3AP1125 is a braking unit accessory for the Altivar Process ATV900 drive system, rated for 800 kW applications in the size 2c form factor. Critical sourcing constraint: this unit cannot be ordered alone. The manufacturer's condition of use requires it to be combined with a standard enclosure — it's a subsystem component, not a standalone buy. For a BOM line, you'll need to specify the enclosure alongside it.
As a braking unit, the VW3AP1125 handles regenerative energy from the motor during deceleration — it dissipates that energy as heat through a resistor bank rather than letting it pump the DC bus voltage up. For the 800 kW rating, this is sized for high-inertia loads or frequent stop-start cycles on a conveyor or winder application. The IP23 plinth allows bottom cable entry and some airflow for heat rejection, but the enclosure it mounts into must be rated for the total thermal load.