In the United States, three-phase power for manufacturing use is typically delivered at 240 volt or 480 volt, 60hz. Transformers are used to change the voltage to meet machinery requirements and protect your manufacturing facility from electrical issues. Step down transformers decrease the voltage while step up transformers increase voltage. A transformer changes electricity voltage using the magnetic field created by current flow around an iron core. Also, voltage is the measure of the electric force or pressure that pushes electrons around a circuit. Voltage is analogous to water pressure in a pipe and current flow is analogous to water flow in a pipe.