In the three-phase AC system, the phase system is matched by the combination of three single-phase systems U1 voltages U2 and U3 in which the phase difference therebetween is 120 °, thus, U2 delays relative to U1, U3 in relation to U2 and U1 in relation to U3, are equal to 120 degrees, evaluating a complete cycle is referring to 360 degrees.
The system is balanced if the three voltages have the same active value as U1 = U2 = U3. By actuating the three single-phase systems together and removing the unnecessary wires, we will achieve a balanced three-phase system. If two identical loads are connected to a single-phase system, this connection can be made in two ways. SD14005 OLP
The first is the series connection, in which the total current of the circuit circulates through the two loads. In this way, the voltage at each load will be half the voltage of the circuit. The second form is the parallel connection, in which the voltage of the circuit is applied to both loads. In this case, the current in each load will be half the total current of the circuit.