[blackdog]

We had several gearboxes driving 25,000 pound drive shafts at 4,000 RPM. Some nitwit didn't follow the unlock from lockout procedure to the letter. He was in a hurry. He forgot to energize the oil pumps to the boxes and started the main machine up. They heated up in excess of 3,000 degrees, went white hot, and caught everything around them on fire. The fire couldn't be put out because the water would have made the cast gearboxes explode. Each gearbox was about the size of a utility van.

The main machine can't be stopped once it's at speed because it takes a half hour to stop. Any faster and you'll rip the footings right out of the foundation and have a steam loaded Yankee Dryer rolling down the nearest highway at 6,000 feet per minute. (about 60 miles per hour)

I immediately installed prove oil flow sensors into the start circuit. An example of auxiliary control circuits and their importance.

[MonicaG]

Great description. Powering automated control systems is important in ways many never think about or understand.