Great Barrington 1886
The first practical AC power delivery system

William Stanley was the mastermind behind the first AC distribution system in North America and the Stanley Transformer which changed the world. The transformer has been called "the heart of the alternating-current system" His system at Great Barrington is very similar to modern electric distribution systems. Engineers before 1886 knew that AC voltage could be controlled using transformers but no one had built a full working system.

Stanley was the first person to understand the behavior of the magnetic core of a transformer, and he was the first to understand the concept of counter electromotive force.

Great Barrington: Battleground in the War of Currents

While Stanley was building his AC system funded by Westinghouse, Edison Company had already installed a DC system in the same town. Stanley's system quickly showed superiority in its use as Stanley kept adding more and more stores and mansions to his system. The DC power system was very limited in distance and did not compete. At the time the residents of Great Barrington did know know the significance of Stanley's system. They were simply impressed to have more electric light available.


of this Power Generation Site:

Notable features: First practical alternating current demonstration with transformers


Single-Phase, Alternating Current
Power Transmission Length: 1500-2000 feet (455+ meters)
Power system built by: Westinghouse financially backed research on transformers, Siemens alternator, and Edison incandescent lights
Notable Engineers: William Stanley, Stanley system based on work of Lucien Gaulard and John D. Gibbs
Maximum Power Output: 25 horsepower steam engine powering one Siemens alternator, 500 volts output, reduced to 100 volts in each home/business


A first prototype transformer built by Stanley in 1885


William Stanley was by hired in by George Westinghouse Jr. to work in his Pittsburgh factory and began to work on the idea of a transformer. Westinghouse had bought the patents of the Gaulard and Gibbs transformers, and the Z.B.D. transformers designed in Budapest Hungary in 1885. This was the first inductance coil device to use the iron core. Before this the open core inductance coils had existed, but could not reliably regulate voltage. George Westinghouse worked on making the transformer square in shape, this was very important because the Gaulard and ZBD transformers were toroidal which was very expensive to make. Stanley worked with Westinghouse in Pittsburgh. He became ill and moved to Great Barrington, Massachusetts (southeast of Albany) in 1885. While in Great Barrington he continued his work. Stanley had been sick in Pittsburgh do the extreme level of air pollution from the Carnage Steel Mills. A doctor recommended he continue his work in the countryside. Continue below.

Electronics Explained:

The Problem of Transmitting Power:

DC power was mainly in used in the 1880's and it was hard to transmit over distance because:

-To transmit over long distance you need high voltage on a skinny wire or low voltage on a wide wire. High voltage on DC is very dangerous, and with low voltage the wire would have to be so thick that it would not be practical. Also with high voltage you couldn't not step down the voltage so it could be used with home light bulbs.

Using the water analogy: imagine that a small wire with high voltage is like a garden hose with high pressured water moving fast inside. Imagine that this hose fills 2 gallon jugs of water in one minute. Now think of a 6" wide drain pipe filled with water. You can deliver the same amount of water to the destination in the same time period without needing so much pressure.

With AC power you also use high voltage to move the electricity down a long wire. AC becomes more practical because once you send the power to the destination, you can use a transformer to change the voltage down to a manageable level. The power is stepped down several times by the time it reaches you home. The power line coming into your home is at 240 volts, from your breaker box it is split into lines of 120 volts for most of your home sockets and 240 for appliance sockets. (The main home socket in Europe and other parts of the world is 240 volts).

Transformer - a device that transfers electrical energy from one circuit to another circuit using inductively coupled conductors. In other words by putting two coils of wire close together while not touching, the magnetic field from the first coil called the primary winding effects the other coil (called the secondary coil). This effect is called "inductance". Inductance was discovered by Joseph Henry and Michael Faraday in 1831.
Now if you would like to change the voltage on a powerline, you could do this by changing current going into the primary coil (voltage stays high). The current level affects the induced voltage on the secondary coil. A changing magnetic field induces a changing electromagnetic force (EMF) or "voltage". To put it simply: by changing the current you can obtain the desired voltage on the other side.



Continued from above - Stanley developed the transformer in the tranquility of his new home in Great Barrington. He designed his own transformer which would revolutionize the industry. His first patented design was induction coils with single cores of soft iron and adjustable gaps in order to regulate the electromagnetic force which affects the secondary coil. See the illustration below:

Above: The first Stanley Transformer that changed the world of electricity

William Stanley

The Great Barrington System:

He used a Siemens steam engine in a rubber mill near Cottage Street that produced 500 volts. He stepped-up the voltage to 3000 and sent the power to Main Street. There he had 6 step-down transformers located in basements to bring down the power to 100 volts so it could be used for lights at each location. There were 36 incandescent bulbs total in all the shops that were lit by the system. The power transmission cable was strung up to the large Elm trees on the street.

He used transformers in parallel to prevent load changes on one device from affecting all other devices downstream.

A transformer built by Stanley used in the first Great Barrington electrification

Photos of the Great Barrington Site:

The Great Barrington countryside in 2010 is much different than in the 1880's, in the time of Stanley it was stripped of all trees to make charcoal which was used to create super hot fires used to process iron ore located in these low mountains.

Siemens single phase AC generators (Alternators) in 1885. This illustration shows two generators in use in London. Stanley would use one of these types of Siemens generators in the rubbermill in Great Barrington. Stanley later wrote Westinghouse that the Siemens alternators proved to be a dissapointment. Stanley then designed his own and sent the drawings to Westinghouse.

The rubbermill owned by Horace Day was rented by Stanley and used as a power house. Part of the Housatonic river was routed under this mill and used to turn the Siemens generator.

The route of the power across the river and towards main street.

IEEE Plaque near the site

Actual remains of the rubbermill or causeway across the river from the viewpoint.

The Rubbermill site and Housatonic River 2010

Rendered vision of the rubber mill as it once stood across the river

Main Street(right), on the corner of the two streets. Wires were most likely sent via the large trees in front of this property, but it is possible it was sent behind, and then turned right to meet main

The row of shops which were first lit by electric light in 1886. The wires supplying power were strung to large elm trees which used to grow on the right.

After the success of the Great Barrington AC system, George Westinghouse, William Stanley, and Oliver B. Shallenberger worked together to create the first commercial AC installation in the US at Buffalo, New York.


The Future of Stanley:

William Stanley later established the Stanley Electric Company in 1890 in nearby Pittsfield Massachusetts. There his company built and sold the first transformers. In 1903 General Electric bought the company and continued to develop transformers and capacitors there. The Stanley Electric Company is the root of GE's transformer and capacitor business.

A postcard featuring the Stanley Electric Company in Pittsfield, MA

The General Electric Story - A Hall of Electrical History Publication (book)
Wikipedia article on transformers
MIT website: Inventor of the Week" William Stanley

IEEE Global History Network: Milestones: Alternating Current Electrification 1886
The Power Makers: Steam, Electricity, and the Men Who Invented Modern America by Maury Klein
. 2009.

Photos by Michael Whelan, Great Barrington Historical Society
Technical information by Steve Normandin, Rick DeLair

Edison Tech Center, Schenectady, NY

Early AC links:

Schaghticoke Power Station and Steinmetz's monocyclic power experiment

Mechanicville Power Station, Mechanicville, New York 1897, HVDC experiements in 1932

Redlands Mill Creek 1 powerhouse Redlands, CA 1893

Folsom Powerhouse, Folsom California 1895

Dolgeville Dynamo Dolgeville Mill, Dolgeville, NY 1879




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