Page 33 - Electromechanical Devices and Components Illustrated Sourcebook

PREFACE

Most of us take our comfortable life styles for granted, unable to fully comprehend
or appreciate the incredibly complex technologies that surrounds us. The very tech-
nologies that allow the society we are immersed in to exist. We go through our lives
without really noticing the enormous infrastructure that supports our comfort, expec-
tations, and even our demands.
Technology plays a critical role in our societal system. Without it, our world
would be a very different place. It is difficult to find anyone who gives the slightest
thought to what happens when they flip a light switch on in the morning. We click
the switch and expect the light to come on. If it doesn’t, we’re annoyed that we have to
replace the bulb. The subtle complexities of a modern light bulb, let alone that of the
power generation and distribution system that allows it to do its job, are out of the
realm of comprehension for most people, and even most engineers.
Those of us that occasionally think about the light bulb, generally considered it
to be an electrical device. After all, the most common ratings on a light bulb are volts
and watts, electrical terms. The fact of the matter is that a light bulb, like most other
electrical appliances, is actually a mechanical device that is designed to use elec-
tricity as its energy source. The globe is designed to deal with extreme heat, rough
handling, rapid cooling, light diffusion, protection from the atmosphere, dirt buildup,
and convenience. The filament must be designed to withstand various shocks, repeated
cycling and longevity, while still producing the light that we require. All of these
parameters are mechanical in nature. The modern incandescent light bulb is truly a
marvel of electromechanical technology.
There are very few manufactured things in the world that do not require the mar-
riage of electrical and mechanical disciplines. You may consider an ordinary garden
rake a purely mechanical device and you would be right. However, what you may
not have considered is the complex electromechanical system that was required to
manufacture the rake, the transportation system that delivered the rake to your local
garden store, the cash register that was used to ring up the transaction, and your car
that transported you and your new rake right up to your yard.
The internal combustion engine would not exist if it weren’t for an electrical igni-
tion system. Higher horsepower engines couldn’t be started without an electric
starter. The starter’s battery would go dead in very short order if the engine didn’t
include an electrical generator for recharging. Modern pollution standards and fuel
economy could not be met without applying sophisticated electrical controls to the
mechanical systems of an automobile engine.
In any appliance there are varying degrees of electrical and mechanical require-
ments. A lawn mower engine for instance has a very small electric component in the
form of a simple magneto ignition system. On the other hand, a desktop computer is
heavily electrical in nature and the mechanical systems are there only to support the
electrical functions. Aircraft of the early 1900s had a very small electrical compo-
nent, oftentimes limited to the engine’s ignition system. Modern aircraft simply
could not exist without the complex electrical and electronic control systems that
help manage the aircraft’s flight envelope. The startling difference between a mili-
tary fighter plane of the first world war and a modern jet fighter is a clear indication
of how electromechanical technologies have impacted our civilization.

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