VAC would be the abbreviation of Volt Altern Current which would be translated Volts of alternating current. The difference between VDC is that its sinusoidal oscillation achieving a more efficient energy transmission.

The alternating current is the energy that we receive in our homes, it is generated in the power plants by means of alternators.

The intensity of this type of current varies with time, and changes direction 50 times throughsecond (50hz). The generated voltage changes in the form of sine wave so it is not constant.

In the image:

1. Current by pulsations.
2. Direct current (DC).
3. Alternating current (AC).
4. Variable current.

The phase ended in industrial installations (recommended for this type of facility) are those formed by three different phases. It is normally found in industries, but also can be found in old residential installation. Facilities include three-phase 5-wire cable 1. phase (black or brown cable) provides electricity. 2. The power phase 2 (brown) provides electricity. 3.Phase 3 cable (gray) provides electricity. 4. Neutral (blue wire) is responsible for the electricity back where it came from creating a circle. 5. Physical cable (two colors) protects the energy absorbing phase of their environment, in some cases this fifth wire is not used, but it should be done for safety. 1. In the image-phase power system three-phase power system 2.

One hertz is one cycle per second, meaning repeating cycle as an event. For example, hertz is applied physics measuring the number of times for a second wave (either acoustic or electromagnetic) is repeated or can be applied, among other uses, to ocean waves that reach the Beach vibrations per second or a solid. The quantity that measures the frequency hertz is called,in this regard, the inverse of the period. One hertz is an oscillation frequency of suffering a particle over a period of one second.