# Electrical Machines

by Ron Kurtus (28 January 2016)

Electrical machines (also known as electric machines) are devices that convert mechanical energy and electrical energy. An electrical generator converts mechanical energy to electrical energy.

An electric motor converts electrical energy to mechanical energy. An alternating current (AC) transformer changes the level of AC voltage and is considered by some also as an electrical machine.

Questions you may have include:

• How does an electric generator work?
• How does an electric motor work?
• How does an AC transformer work?

This lesson will answer those questions.

## Electric generator

The way an electrical generator works is that mechanical energy turns the shaft going into the generator. The rotation moves electrical wires past permanent magnets, thus creating an electrical current in the wires. The current may be alternating current (AC) or direct current (DC), depending on the configuration of the commutators on the shaft.

## Electric motor

An electric motor is basically a generator in reverse. Electrical current is fed into the motor wires, which are wrapped around an iron core, thus creating an electromagnet. The magnetic field then repels the permanent magnet around the core, thus causing the shaft to rotate.

An electric motor can be an AC motor or DC motor, depending on the commutator configuration.

## AC transformer

An AC transformer consists of an iron containing two wrappings of insulated wire. The input voltage is converted to an output voltage, according to the ratio of the number of turns of the wire.

AC voltage can be increased or decreased according to the the ratio of the turns of wire.

There is debate as to whether an AC transformer is really an electrical machine since there is no resulting motion.

## Summary

Electrical machines or electric machines are devices that convert mechanical and electrical energy. An electrical generator converts mechanical energy to electrical energy. An electric motor converts electrical energy to mechanical energy. An alternating current (AC) transformer changes the level of AC voltage and is considered by some also as an electrical machine.

Always do your best

## Resources and references

Ron Kurtus' Credentials

### Websites

Electrical machine - Wikipedia

Electric machine - Wikipedia

Electromechanics - Wikipedia

Machines Resources

## Questions and comments

Do you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. I will try to get back to you as soon as possible.

## Students and researchers

www.school-for-champions.com/machines/
electrical_machines.htm

Please include it as a link on your website or as a reference in your report, document, or thesis.

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