# How to Calculate Transformer Load

••• transformateur Ã©lectrique image by Lounatiq from Fotolia.com
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A transformer changes alternating current (AC) voltage from one level to another for power companies, appliances and chargers. But the size of a transformer has little to do with the voltage, and everything to do with the amount of electricity it provides. Electricians and technicians refer to the equipment a transformer powers as its load, be it machinery, appliances or electronic components. The load can be measured in amps, watts or volt/amps. To calculate load, you must understand certain electrical terms and formulas.

••• Power Pole and Rainbow image by Scott Griessel from Fotolia.com

Inventory all the equipment the transformer powers. Make a list of the components, lights, appliances or machinery that the transformer will operate. Add the amount of current, watts or volt/amps that each draws. There should be a tag or label on all equipment telling the amount of current or power it draws.

••• High Voltage Transformer image by Andrzej Thiel from Fotolia.com

Convert the power to equivalent values. Arrange the values into two columns on the list. Label the first “current” and the second “watts” or “volt/amps.” Use the formula power equals volts times amps, or (P=IE) t, make conversions.

Add up the total current in amps for the first column and the watts or volt/amps in the second column. The sums equal the transformer load expressed in the three terms.

#### Things You'll Need

• Pen or pencil