What is the difference between phase voltage and phase current?

The terms 'phase voltages' and 'phase currents' are used in three-phase alternating-current systems, to distinguish them between 'line voltages' and 'line currents'.

In a three-phase system, the generator has three coils which generate voltages that are displaced from each other by 120 electrical degrees. The generator is then connected to the load using three conductors, called line conductors. The generator's three coils are described as 'phases', and the generated voltages are called 'phase voltages', while the currents flowing in them are called 'phase currents'. The voltages between the line conductors are called 'line voltages' and the currents flowing through the line conductors are called 'line currents'.

Similarly, the loads themselves represent 'phases', and the voltages appearing across the loads are called 'phase voltages' and the load currents are called 'phase currents'.

Depending on the configuration of the phases (they can be connected in 'delta' or in 'star'), the line voltages either equal the phase voltages or are 1.732 times larger than the phase voltages.