To force rotating equipment to exceed its designed maximum rotational speed. This condition generates excessive centrifugal forces that can cause catastrophic mechanical failure, such as turbine blades detaching or flywheels shattering. Control systems usually include automatic trips to cut power or fuel before this threshold is reached.
Heard on the job
The governor failed and the diesel started to overspeed, so we had to hit the emergency stop.
Insider tip
A runaway diesel pulling in crankcase oil is a classic overspeed scenario that cannot be stopped by cutting the ignition.