Physics - Electromagnetics?

Question

Thomas Edison proposed distributing electrical energy using constant voltages (DC). George Westinghouse proposed using the present AC system. What are the reasons the Westinghouse system was adopted?

Answer 1

AC current can be transmitted long distance, and the voltage of the current can be changed with transformers. DC current, though more powerful, can not be delivered over long distance without significant power lost, which limit its application to cities only. For more info check Wikipedia or other sources:


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Answer 2

DC current is no more powerful than AC current. An ampere is an ampere. The loss mechanisms are the same for AC or AC. The loss term is proportional to the square of the current. The key to either AC or DC low loss transmission of power is to up the voltage to decrease the current and thereby increase the efficiency. High power, long distance transmission of power is done using both AC and DC. In the Pacific Northwest we have the DC intertie that runs from Washington down to California. Before the advent of high power solid state devices it was easier to generate, transmit and distribute using AC. One could make the case today that DC can be made about as efficient. But there is a huge installed base of AC equipment so AC is the dominant method.