# 3.2: Electricity and Magnetism

• Contributed by Camosun College

Electricity and magnetism

There is a direct relationship between electricity and magnetism. If there is current flow in a conductor there will be lines of force created around the conductor. If you could look at the magnetic field formed around a current-carrying conductor, it would look like Figure 8.

1. Electromagnetic field
2. Opposite currents repel
3. Like currents attract
4. Flux in a loop
5. Electromagnet
6. Simple generator
7. AC sine wave

If it takes one second to complete the cycle from A to B, we would say the frequency is 1 hertz. Household utility AC current is supplied to the customer at 60 hertz, meaning 60 cycles per second.

Single-phase power supply

Single-phase electric power refers to the distribution of alternating current electric power using a system in which all the voltages of the supply vary in unison. Single-phase distribution is used when loads are mostly lighting and heating, and with a few large electric motors. Single-phase power comprises two independent voltages that are carried on two separate conductors. The two hot lines are called Line 1 and Line 2. They are typically found in residential and small commercial applications.

Three-phase AC power supply

Three-phase electrical power refers to a type of electrical power distribution in which three or more energized electrical conductors are carrying alternating currents. Examples of three-phase power systems are industrial applications and power transmission. Three-phase power supply is used to power large motors and other heavy loads. A three-phase system is generally more economical than equivalent single-phase or two-phase systems at the same voltage.

Three-phase power comprises three independent voltages that are carried on three separate conductors. The three hot lines are called Line 1, Line 2, and Line 3. Three-phase power is typically found in commercial and industrial buildings.

Now complete the Learning Task Self-Test.