When you think of how difficult a task it was trying to measure something which you cannot see, cannot taste, cannot grasp and cannot hear, you will realize how great of an accomplishment it was for engineers like Oliver Shallenberger at Westinghouse to invent the watt-hour electric meter.
Since 1888 many other kinds of useful meters have been developed. When
the average person thinks of a great invention, they think of the light bulb or
television. However they don't realize that without good measuring devices
almost none of our modern inventions could exist!
In this page we tell just a bit about meters and provide you links to some more technical explanations. If you ask Robert N. Hallthe inventor of the semiconductor laser (used everywhere in the world today) what his greatest invention was, he will tell you it was the lithium drift detector. From someone who really understands technology that tells you a lot about the importance of the tools we use to measure.
1.) Types of Meters
1.) Types of electric meters:
There are
more types of meters, detectors, and measurement devices than could be possibly
listed here, but we will list a few of the most prominent which have really
changed our world.
Watt-hour Meter –
This is one of the
most important meters ever invented. This measures the amount of AC current
used by a customer. With an accurate way to measure power devised in 1888, this helped make the electrical
grid economical and in the 1890s the electrical industry flourished. On the
business side of things it was necessary to measure use as it makes for a fair
way to charge customers. The traditional watt-hour meter uses a disk that spins
due to electromagnetic fields. A counter measures the number of rotations. The
more energy one uses, the faster the disk spins.
.
detects
electric current .This
was historically the name given to an 'ammeter', it works by using coils of wire on a base of a needle in
between two permanent magnets. This is one type of "moving coil
meter".Ammeter -
measures electric current (amperes) There
are many types of ammeters today. Digital ammeters use a shunt resistor
with volt meter and compute formulas to display the value.
Volt Meter - measures voltage (electrical potential) across a circuit
Volt Meter - measures voltage (electrical potential) across a circuit
Ammeter –
measures electric current (amperes) There are many types of ammeters
today. Digital ammeters use a shunt resistor with volt meter and compute
formulas to display the value. Volt Meter - measures voltage (electrical potential) across
a circuit
Timeline
of the History of Electric Meters:
Here is a
short list of important events in the history by the Edison Tech Center.
1800 The electric age begins with Volta's battery
which sparks many inventors and scientists around the world to start to
experiment with electricity. There are no standards of measurement or meters to
measure this force. No one yet understands what electricity is and therefore it
takes another 90 years before more scientific explanations help to break down
electricity into its elements which then are assigned standards by the IEC in
Chicago and Paris in the 1880s-1890s.
1866 Transatlantic telegraph was completed. Basic
galvanometer-type meters were used to set up telegraph systems.
1879 Thomas Edison desperately needs a way to
measure the electricity his customers would use. He developed a chemical meter
with two rods of copper in a solution, as power was used one of the electrodes
dissolved, showing by mass how much power had been used. This invention was not
ready for use when the Pearl Street Station started working with customers, so
early customers got electricity for free. After a year Edison started using the
chemical meter but it was not accurate and customers were unhappy.
Interesting
Fact: JP Morgan ran 106 lamps from 3pm-6am but never paid more for this use
since he only paid by the number of light sockets and for the physical bulb
purchases.
1880s Elihu Thomson develops
a chemical meter similar to Edison's except it used zinc sulphate bath which
worked much better. Edison's companies immediately started using Thomson's
meter as they were desperate to solve the problem of metering.
1880s Thomson builds one of the first reliable
wattmeters. He used solid silver bars and brushes with an aluminum disk with a
small motor. Once again everyone including Edison used Thomson's meter as a
standard.
1880s Edison
vs. the gas industry: Thomas Edison adopted
Thomson's meters and changed to a model that charged customers for electricity
use, however this angered many customers who had been convinced to change over
from gas lamps because of the fact that the flow of electricity was free.
Edison doesn't get enough credit for his taking the brunt of the gas vs.
electricity battle. We have to thank Edison for hanging in there and operating
at a loss for years before getting profit.
1886 Edward Weston develops a moving coil
galvanometer type meter with stable permanent magnet which becomes the basis of
Amp, Volt and Watt meters for the next 100+ years.
1880s Edward
Weston refined a watt-hour based off of Thomson's work
1887 Oliver
Shallenberger develops the first accurate voltmeter at
Westinghouse with Philip Lange
1888 Oliver Shallenberger at Westinghouse develops
a meter that is close to the modern watt hour meter and sets the new standard.
1890 Only 5% of US homes were equipped with
electricity. Arc lamps for public street lighting and trolleys were the most
profitable employment of the technology. The AC revolution of the 1890s would
change that.
1892 J.A.
Fleming starts work on what would become the vacuum tube in the 1900s.
1890s Elihu
Thomson continues to improve electric meters. Thomson has been working with AC
power since the 1870s and has more experience in the area than most people
around at the time.
1890s The
IEC - International Electrical Congress creates standards for measurement of
electricity
1896 William Stanley develops
a static ground detection meter. This method is still used today to help ground
vehicles and facilities as a measure of safety.
This timeline was created by the Edison Tech
Center, report copyright infringement by content strippers who target timelines
like this.
1916 High Voltage Measurement: Chubb and others
develop meters that use predecessors to vacuum tubes and make the first
somewhat accurate ways to measure this dangerous and difficult form of power.
Before this point they used the crude method of measuring the distance an
electric arc could travel through air or a tube to figure out the high voltage.
1922 E.B. Moullin create the first real vacuum
tube voltmeters using improved triodes.
1930 The IEC establishes more
standard electrical units including: Hertz, Oersted, Gauss, Maxell, Gilbert,
Var, and the Weber
1957 Rosewell Gilbert (of Weston) developed the
dual slope analog-to-digital conversion circuit was developed and allowed for
stable noise-reduced measurement by digital means.
1970s Digital multimeters begin to
appear as the cost of solid state devices drops
1970s Vacuum tube meters finally kill off moving
coil galvanometers which were still in use by large companies. Many employees
take the older meters home and these enter collections including the Edison
Tech Center's collection later on.
1990s Digital multimeters outnumber tube-based or
magnetic multimeters
2000s Digital multimeters are produced by many
companies, some reach prices as low as 90 cents per meter while others made by
Fluke or Milwaukee have a higher standard of quality and reliability and fetch
prices in the hundreds of dollars.
[edisontechcenter.org]
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