Failed Load Bank Testing, which is done annually (Thermoflo performed two tasks for a maintenance contract. There is a Load Bank Test performed, and every two weeks, they run the gens to see how they perform with minimal load), was being done to generators 3 and 5. This simulated electrical test (not simulated; it is a live test) adds electrical load in increments of 25% over an extended period. At a 75% load, generator 3 began to lose turbo pressure. (Confirmed) Before the testing, we understood that a fuel injector inside the turbine failed. During the testing, this failure caused fuel to dump into the cylinder, which displaced the lubricating oil. Without the lubricating oil, it overheated, causing the piston to melt, and then seized the engine. Replacement Cost $208,750.00.