Contents
Where does neutral current go?
Neutral is a circuit conductor that normally completes the circuit back to the source. Neutral is usually connected to ground (earth) at the main electrical panel, street drop, or meter, and also at the final step-down transformer of the supply.
Does 3 phase have a neutral?
Three phase systems may or may not have a neutral wire. A neutral wire allows the three phase system to use a higher voltage while still supporting lower voltage single phase appliances. Three is the lowest phase order to exhibit all of these properties. Most domestic loads are single phase.
What does current flow through neutral in a single phase?
The magnitude of the current depends on the level of imbalance. It depends on the type of service. Here in north america we have 120/240 volt split three wire single phase service to most homes and many apartments. There is 120 volts from either hot wire to neutral and 240 volts between the two hot wires.
How are three phase loads connected in a system?
Three-phase loads can be connected together in two different forms: wye and delta. Fig. 1.9 illustrates a wye-connected three-phase load. In this system current through each phase of the load, or the phase current ( Iφ ), is the same as the current through each of the three-phase lines from the source that are also known as line currents ( IL ).
Why does the neutral current carry the unbalanced amount of current?
On a three-phase system where the dominant loads are single phase, the neutral carries the unbalanced amount of current. Even though the loads may have been balanced at one time, the normal changing of the system may have caused a large unbalance, leading to a large neutral current.
What happens when all three phases of a DC circuit are balanced?
If all three are balanced, the return current for any one phase are carried by the other two. Again, the service neutral only carries any unbalanced load. For the purposes of understanding the general scheme, you can analyze the circuit as if it were a DC circuit.