Edison 3-Wire Circuits Flashcards Preview

Electrical Theory Period 1 SAIT-Alberta > Edison 3-Wire Circuits > Flashcards

Flashcards in Edison 3-Wire Circuits Deck (11)
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1

An Edison 3-wire system has three conductors, what are they?

  • 2 ungrounded conductors with equal but opposite potential
  • 1 neutral conductor usually at ground potential.

2

What are three advantages of using an Edison 3-wire system?

  • Two different voltages
  • Less conductor material
  • Less line loss

3

In an Edison 3-wire system, the neutral conductor carries only the "_____" load.

Unbalanced.

4

What are the steps required to solve an Edison 3-wire circuit?

  • Determine the magnitude and direction of line currents. (Polarities)
  • Use Kirchoff's current law to determine currents at junction points.
  • Calculate the line drops in the circuit.
  • Use Kirchoff's voltage law to calculate load voltage drops.

5

A balanced load is when...?

Equal currents flow through the loads.

There is no neutral current.

6

In general and ignoring line drops the load with the higher current flow has the "_____" voltage drop across it.

Lower.

7

What are the effects of a high resistance neutral conductor in an Edison 3-wire system?

The load voltages will be very unbalanced due to the large line drop on the neutral conductor.

8

How can a high resistance neutral occur?

An improper connection can create points of high resistance.

9

In a balanced load Edison 3-wire system, what happens to the load voltage drops if the neutral conductor breaks?

Nothing changes since the neutral had no current to begin with.

10

In an unbalanced Edison 3-wire system, what happens if the neutral conductor breaks?

The circuit becomes a series circuit so the high resistance load will take the majority of the voltage drop.

11

Would the neutral conductor ever be fused in an Edison 3-wire system?

No, if the neutral is opened on a typical three wire system the voltages could shift to very unsafe values, so they are never fused.