Originally Posted by
ELECTRIC EEL
... for any eletrical equipment to work, that on one end had to be voltage and on the other side it had to have no voltage...
Incorrect statement. Voltage itself does not do anything. A voltage
DIFFERENCE between two points does!
Originally Posted by
ELECTRIC EEL
so when the voltage goes to a three phase motor where does it go?
So a motor runs on a voltage difference.
With one phase that voltage is AC to one winding. The voltage is sinusidal, and - in the US - with a frequency of 60 cycles. With two wires the applied voltage is 180 degrees shifted, i.e. when one side is positive, the other side is negative. Note that the voltages at both points always cancel each other out. At the transformer one side is connected to earth (called neutral), the other side is called "hot".
Three phase is also 60 cycles per second, but the three windings of the motor receive now each voltages that are 120 degrees shifted in phase between each other. So if the 3 phase 220 Volt voltage on wire 1 is momentary nill Volt, than wire 2 is about + 180 volt, and wire 3 is about - 180 Volt.
The resulting voltage of these three voltages is again always nill, whatever each individual voltage is. Therefore there is no need to connect a forth wire to the common point at all.
And at the transformer the situation is as with one phase : the common point of all three phases is connected to earth (the neutral is used only for one phase connections). And each three phase wires is "hot".
Capice?