A power trip

A new transformer is installed in Moose Lake. Employees needed to use a crane to lift the transformer in place. 


What does a squirrel, lightning strike and air conditioner have in common?

All three can shut down a transformer and cause residents' power to go out.

Most people only think about a transformer when they hear a loud sound similar to a car backfiring and their power unexpectedly shuts off. The transformer plays an important part of bringing power to homes and businesses. But what does it do?

The transformer transforms or reduces voltage from a primary source to a usable size, Harlan Schmeling, superintendent of Moose Lake Water and Light explained. He said voltage traveling through the wires is much higher than homes and businesses can handle. The exact amount of voltage through the wires depends on the size of the city. Once the electricity reaches its destination, it is reduced through the local transformer and on to its destination. The transformer can also increase the voltage traveling through the wires when it is necessary. 

A transformer is a hollowed-out magnetic iron core with wire wrapped on each side, according to science.com. The electricity enters through the wires wrapped around one side and leaves through wires on the other side.

The electricity rides through the power lines, then through a transformer where it is downsized for the business or home. 

A regulator is similar to a valve that regulates the voltage and keeps it at a steady rate as it travels through the wires to the homes and businesses.

There are a variety of reasons why a transformer suddenly shuts down.

A common reason in this area occurs when customers expand their usage at home by adding an air conditioner unit or other large appliance, Schmelling said. It adds more draw and overloads the transformer which causes the fuse to flip and kill the power to the transformer. 

“A lot of times the loud sound people hear is the fuse shutting down the power,” Schmelling said. “It sounds like a 12 guage 

shotgun going off.” 

An overload from a lightning strike can shut down a transformer, as can damage by squirrels or when snow or water gets inside the unit and disrupts the circuitry. 

“Be careful around power. Water and electricity don't mix,” Schmelling cautioned. “It doesn't take much to stop a heart.”

Transformers can be found at the top of a power pole or on the ground in areas where the power lines are buried underground. They look like a gray cylinder at the top of the power poles, Schmelling said. The ones on the ground are usually painted green to blend in with the foliage.

They come in a range of sizes and have an average life expectancy of 40-60 years. The oldest one at the Moose Lake facility was dated 1956 and is decommissioned now, Schmelling said. He added that a year can go by without a transformer malfunctioning, but sometimes four can go in one year. 

“Electricity does some funny things,” Schmeling said. “Every situation is a little different.”

He said he could not comment at the recent fire at the substation that caused power to go out during extremely cold weather. The case is under investigation.


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