REGULATION IS THE WRONG WORD

When you hear the word "regulation," it probably raises your hackles as it should, for you are thinking of government regulation. But engineers have long used the word in a different sense, namely, reacting to the signals of a feedback loop, and in that sense the government interferes, destroys, devastates, commands, prohibits, steals, robs, embezzles and kills (FDA!), but there is one thing it does not do: regulate.

James Watt is generally considered the first to have used auto-matic regulation, and the name he gave to the device again had an unintended but unfortunate political ambiguity: governor.

Watt's device is shown on the right. The most striking thing about it, as all European children of my generation knew (thrashers used to be driven by steam engines) are the two flyballs F, traditionally made of shining brass, kept spotlessly clean. The governor shaft p was driven by the steam engine, and its rotation caused the brass balls to rise by centrifugal force, the higher the faster the engine ran. This would raise the slide S, compressing the spring R until an equilibrium position was reached. (Centrifugal force is proportional to the square of the angular velocity, the force of a spring is proportional to its compression). But the important point is the lever L, which in Watt's case raised or lowered a slide valve (not shown) feeding more or less steam to the engine. Since the lever was in a stable position, the amount of steam fed to the engine was constant and it ran at a constant speed.

Now suppose that for some reason the machine deviated from this stable speed and began to run faster. Then the brass balls would spin faster, and through the mechanism just described, cut down on the steam fed to the engine until it slowed down to its regular speed. If the engine slowed down (say, because a bigger load was put on it), the balls would spin more slowly, the spring would push down, and the lever L would open the slide valve to let in more steam.

Walt's governor is still in use on steam engines. (Perhaps there are steam engines where the whole job of the governor has been taken over by a microprocessor, but that would seem as incon-gruous as a horse cart with electric turn signals.) The one impor-tant component not shown in the figure is a thumb screw at the top of the shaft. It pre-compresses the spring and thus determines what the constant speed of the steam engine shall be.

James Watt was not the only one to invent the steam engine (there was Newbury and others who had somewhat different designs), but he appears to be the only one to have outfitted his model with a governor, giving rise to an important engineering dis-cipline: regulation and control.

He was thus the first regulator and he had as little to do with government as regulation itself