Abstract: A method for simultaneous testing of individual components in multiple three phase inverters, each connected to a common source of direct current electric power and being coupled to supply power to a respective one of a plurality of three phase loads, involves the steps of monitoring the voltage applied to the inverters and the current at each output phase terminal while gating each switching device in each inverter momentarily into conduction in sequence from a first switching device in a first phase to a last switching device in a third phase until an input voltage drop or an output current is detected. In response to a detected voltage drop, the sequence of gating is interrupted and advanced forward to the next occurring phase. If phase current is detected in any phase during gating, the inverter generating the current is disabled.