[Search Doc Brown's science website]

SITEMAP   School-college Physics Notes: Electricity-magnetism 11.5 The AC motor

UK GCSE level age ~14-16 ~US grades 9-10 Scroll down, take time to study content or follow links

Motor effect of electric current: 11.5 How a simple a.c. AC electric motor works and uses of electric motors

Doc Brown's Physics exam study revision notes

INDEX physics notes: motor effect of an electric current and applications

11.5 A simple a.c. electric motor

How does a simple a.c. AC electric motor work?

diagram of how an a.c. electric motor works gcse physics igcse slip rings brushes coil commutator magnet

Diagram of a simple a.c. electric motor

The a.c. power supply is connected to the rotating coils of the armature by two slip rings and carbon brush contacts.

Note the difference - two slip rings in an a/c. motor, instead of a split-ring commutator in a d.c. motor.

As the coil rotates, the direction of the current passing through the coil reverses direction.

When the coil has moved through half a turn, the direction of the current has reversed.

This ensures the force, produced by the interaction of the two magnetic fields, always operates in the same net direction, so the rotation of the coil is always in the same direction (clockwise or anticlockwise, depending on the poles of the permanent magnet).

The usefulness of electric motors (d.c. or a.c.)

Where do we start!

There are hundreds of uses in the home, in industry and transport systems.

They speed up many processes once done by manual labour, and increase the efficiency of machines once powered by coal (eg steam locomotives) or wind (eg windmills).

Electric motors power semi- or fully-automated production lines e.g. packaging of food, car assembly lines etc.

You can build electric motors of any required power from little motors in toys to powerful machines in heavy industry.

Powerful electric motors (ac or dc) drive electric trains.

Electric cars are slowly replacing fossil fuelled cars.

Appliances in the home powered by electric motors:

microwave cooker, food mixer, hair dryer, toothbrush, CD player,

we would be rather lost without all our electrically powered 'gadgets'!

An a.c. AC electric motor powered locomotive

This British Railways 'INTERCITY' electric locomotive has a maximum speed of 140 mph (225 km/hour) derived from a 4700 kW a.c. electric motor powered from 25 kV overhead power lines. Note that electric motors can be a.c. or d.c. current driven.

INDEX physics notes: motor effect of an electric current and applications

Keywords, phrases and learning objectives on the motor effect in a simple a.c. AC motor

Be able to interpret a diagram to explain how an a.c. AC electric motor works.

Be able to describe some uses of an a.c. AC electric motor.


TOP of page

INDEX physics notes on motor effect of an electric current

ALL my electricity and magnetism notes

email doc brown - comments - query?


BIG website and using the [SEARCH BOX] below, maybe quicker than navigating the many sub-indexes

Basic Science Quizzes for UK KS3 science students aged ~12-14, ~US grades 6-8

BiologyChemistryPhysics for UK GCSE level students aged ~14-16, ~US grades 9-10

Advanced Level Chemistry for pre-university age ~16-18 ~US grades 11-12, K12 Honors

Find your GCSE/IGCSE science course for more help links to all science revision notes

Use your mobile phone in 'landscape' mode?

SITEMAP Website content Dr Phil Brown 2000+. All copyrights reserved on Doc Brown's physics revision notes, images, quizzes, worksheets etc. Copying of website material is NOT permitted. Exam revision summaries and references to GCSE science course specifications are unofficial.

Using SEARCH some initial results may be ad links you can ignore - look for docbrown

INDEX physics notes: motor effect of an electric current and applications