For example, a house usually uses 120V AC (in the United States) and a car generally uses 12V DC. [2] X Research source You can use an online amperage calculator to make things even simpler.
Amps = Watts/Volts
A coulomb is the SI unit for electric charge and is defined as the amount of charge moved in one second by a constant current of one amp.
Amps = Watts / (PF X Volts) where the power factor (PF) is a unitless value.
Solving for three phase AC power has more variables than single phase. You will have to decide whether you are using line to line or line to neutral voltage to calculate amps with three phase.
