This paper presents an interesting approach for hardware-in-the-loop testing of voltage source inverters for drive applications. For this purpose the inverter under test is not connected to a real machine, but to a second inverter instead, which behaves like an electrical machine. The power capability of the so-called "Virtual Machine" is increased by sequential switching of parallel connected standard inverters. The parallel connected inverters can be of the same type as the inverter under test. Hence there exists no power limit for drive inverter testing with respect to the product range of the manufacturer.