If we were to ask you to describe Access Energy Cooperative’s system, you might say, “Poles, wires and those round grey things.” Round grey things? That is often the description given for transformers, the piece of equipment crucial in converting electricity to a voltage that is safe for use in homes and businesses. So, how do they work? They transform the voltage of the electricity that passes through them.

Electricity loses voltage as it is transmitted, due to the resistance in wires and other components. As a result, higher voltages are used to offset these “line losses.” At the power plant, generators produce electricity at very high voltages and use transformers to step up this voltage. Since the power plants are a long way from the end user, high voltages are necessary to survive the trip over the system to where it is needed.

Transmission lines connected to substations are brimming with transformers and other control gear. Here is where the transformers step down the voltage to safer, more manageable levels. Depending upon the distance involved to the furthest member and the amount of load served, distribution voltages can range from 7,200 to 24,900 volts. A couple more step-downs and the electricity arrives at your home at 440 volts.

Regardless of the shape and size of a transformer, they all work in the same manner. Transformers have two sides, a high-voltage side and a low-voltage side. In normal operation, electricity flows into the transformer on the high-voltage side, where it goes into a coil of wire usually wound around an iron core. As the electricity flows through this coil, it creates a magnetic field that “induces” a voltage in the other coil. Here is where transformation takes place. Each coil has a different number of turns. The greater the number of turns, the higher the voltage. The coil on the high side will have more turns than the one on the low side. As a result, the voltage induced on the low side is less. Then transformation occurs.

It is important to note that transformers work in both directions. Electricity flowing in on the low side is stepped up to the voltage of the high side. This is why Access Energy Cooperative educates members on proper connection of home generators. A generator feeding 220 volts into a residential transformer will produce whatever voltage the transformer is rated for on the other side, creating a deadly risk for our line crews and your neighbors. So please, connect your generators according to the manufacturer’s recommendations, or give us a call at 866.242.4232 for advice.

Source: Tom Tate

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