After many years of experimenting with the 5-MW thermal blowdown generator, much knowledge has been gained about its construction and operation. Measurements are described for obtaining useful information about the system. The most important parameters that have been determined are the density and size of dust particles, the density of impurities, seed ratio, electron temperature and density, streamer velocity, and pressure. The maximum power output that has been reached is 423 kW with an enthalpy extraction of 8.5%. The most important functional conclusions that can be drawn about the generator are 1) the hot flow train inside the magnet should not contain any metal components except for the electrodes because shortcircuiting gives a great increase in the exit pressure; 2) water contamination should be reduced to less than 100 ppm; and 3) the load resistors must have a low inductance in order to provide good ignition conditions for the streamers.