In alternating current, the flow of electric charge periodically reverses direction. During this process, the voltage varies continuously. In the US, and anywhere else with 60Hz power, this cycle occurs 60 times per second. Considering a sine wave as the usual waveform of alternating current, one can say that voltage reaches zero twice per cycle. It means, 120 times per second in a 60Hz power, the power supplied is zero. This process might not affect electronic appliances, but it does have significance for heavy loads and equipments such as motors.
Three phase power works with three alternating currents from three electric circuit conductors. These three alternating currents are separated and reach to their peak value of amplitude at different times. In relation to the alternate current from one of the electrical circuit conductors, the other two currents are delayed by one-third and two-thirds of one cycle. It means total power supplied by these three alternating-currents remains constant.
Three phase power is a widely accepted way of alternating-current electric power generation, transmission and distribution. Most of the electric power distribution grids across the world use this method to distribute power. Generally, larger motors and other heavy loads are powered by three phase power.
Three phase power is very economical compared to equivalent single and double phase power, because it uses less conductor material to supply power. The three-phase system was introduced and patented by Nikola Tesla.
Most households are single phase powered. Three phase power is generated in a power station using three coils of generator. A transformer changes the voltage to optimize transmission and nullify the losses. Later on, this voltage is converted to standard utilization before it is supplied to customers.
Related Posts:
Basic Principles of an Alternating Current (AC)
Nikola Tesla
