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No Title 742

Electricity is one of those things in nature you can’t really see. We just know it’s in our house or business because our appliances tell us it is. We flip a switch or push a button and the lights come on, the TV springs to life, the computer starts humming.

The closest most of us come to actually “seeing” electricity is when we look up at those wires overhead, strung from town to town, pole to pole, house to house. But what are those metal cans hanging from the poles?

Most of us already know. They are called transformers, devices that usually “transform” the power that’s carried by high-voltage electric lines down to the lower voltages we use every day in our homes and businesses.

Although they’re overlooked and taken for granted by just about everybody, transformers are vital when it comes to getting power to you.

What you probably don’t know is that thousands and thousands of them are made behind a small, unpretentious office building in Louisville. It’s the same address, 4515 Bishop Lane, that is home to the Kentucky Association of Electric Cooperatives (KAEC) and Kentucky Living magazine.

A hallway leads from the co-op offices at the front of the building to a 160,000-square-foot factory, where KAEC manufactures the transformers sold by the United Utility Supply Cooperative, or UUS, as employees call it. The KAEC-UUS combo makes up one of the largest transformer manufacturers and distributors in America. As a co-op itself, UUS is owned by 230 electric cooperatives in 17 states.

How busy is United Utility Supply?

Gary Burnett, vice president, says the company sells 50,000 to 60,000 transformers a year. That’s quite a leap for this co-op that started out in 1951 as a special services department of KAEC, created out of a need to have older transformers repaired.

Six years later KAEC took the step of adding a conveyer belt to the transformer assembly operation. Some milestones since then: In 1996, the one-millionth transformer went out the door. In 1999, total sales surged past $1 billion. United Utility Supply sells transformers and related equipment to co-ops and other utility distributors in 30 states. Today, United Utility Supply ranks 64th out of the top 200 electrical distributors in the nation, according to Electrical Wholesaling magazine.

Just in Kentucky, there are 26 electric cooperatives that are members of the Kentucky Association of Electric Cooperatives. Burnett says power travels through 82,000 miles of electric lines in Kentucky to reach 630,386 co-op customers. That means a whole lot of transformers are being used, too.

Add to that the fact that UUS also works with more than 100 other companies that make support materials for the industry, from safety gloves to the nuts and bolts that attach the transformer to the pole, and the volume of business is tremendous.

“We average $70 million in total sales,” Burnett says.

And he says demand continues to grow, thanks to economic development in rural areas, for example. That growth brings in more strip malls, subdivisions, vacation homes, and the like. And Burnett points out that today’s house uses a lot more energy than one built, say, in the 1950s and ’60s—roughly 15-20 times more energy.

Why? Because new houses today tend to be not only quite a bit bigger, but they need more electricity for air conditioning, computers, and lots of appliances, even though these items are energy-saving.

Although the transformers are built to last 30 years or more, they can go bad.

“The largest factor for failure is storm-related,” Burnett says. Most of the time, that means lightning.
So UUS and KAEC keep at it, employing about 175 people to play a part in the process.

Basically, a transformer is made up of two sections of metal—wound wire and metal strips. Those two parts are combined into an assembly that controls the amount of electrical voltage that is passed on to the customer, typically 110- and 220-rated electric current.

Completed transformers are moved to a warehouse, the Cooperative Distribution Centre, just down the street on Leghorn Drive. The CDC, as it’s called, is a huge box of a building, with 14-foot ceilings and 180,000 square feet of floor space.

Transformers, perhaps 5,000 of them, look like cousins of the Star Wars stumpy robot R2-D2 as they stand on wooden pallets, ready to move out. Shelves hold hundreds of types of support hardware as well.

The CDC uses 15 Freightliner trucks and 55 semi-trailers to ship United Utility Supply’s product to its customers and other UUS warehouses in Alabama, Illinois, Tennessee, Ohio, and Pennsylvania.

Before KAEC purchased the building in 2002 to store the transformers coming off the line, those finished transformers were simply stored outside, says Charlie Drexler. After 17 years with the company, Drexler, KAEC’s director of engineering and quality assurance, shakes his head as he considers the huge improvement.

It doesn’t hurt to have up-to-date-technology at his fingertips, either.

With the company’s computer software able to locate any item at any time, Drexler says, “If I have a problem with a transformer, I know exactly where it is.”


Five days a week, workers are busy building transformers inside the Kentucky Association of Electric Cooperative’s manufacturing plant, producing transformers for sale by the United Utility Supply Cooperative.

In one area, steel is cut from huge 5,000-pound rolls and shaped into cylinders to make the exterior tank of pole transformers. The tank is electrostatically painted in an enclosed powder paint room.

In another area, bands of steel are tightly wound and shaped into an oval core and baked in a 1500° F oven. Nearby, wire is wound into coils.

In the assembly area, the core and coil are then combined into one piece. Together, this makes it possible for electricity to travel in and out of the tank at different voltages.

The assembly is baked to dry any moisture; the heat also bonds insulating epoxy paper to each layer of wire. An employee proudly places the UUS and American flag stickers to the outside of the tank, along with numbers identifying the kilovolt-ampere size of the transformer. The internal assembly is then mounted inside the tank.

Exterior electrical connectors and a compression-fitted lid are attached.

The tank is filled with mineral oil, and the lid sealed. The oil not only ensures that all air and moisture has been removed, it acts as an insulator and transfers heat to the outside of the tank.

Lightning arresters are added, to protect the transformer once in service.

A series of mechanical and electrical tests are performed, such as checking for leaks and testing voltage. The transformer is assigned a serial number and bar code, packed onto a pallet, and forklifted into a truck for transfer to the storage facility nearby.

KAEC manufactures about 200 pole-mounted transformers per day; the company deals in about 80 stock sizes. It also produces 28 pad-mounted transformers per day—those green boxes you see sitting in yards that are used for underground utilities. In addition, they repair transformers and test and sell protective gloves used by lineworkers.


• 4,000 feet: length of wire in an average transformer

• 375 pounds: weight of average transformer

• 20,000 gallons: amount of mineral oil used in one week to fill transformers at UUS

• 130,000 pounds: amount of core steel used in one week at UUS

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