Dynamos:
A dynamo is a electric generator for processing of magnetic flux into electricity by the phenomenon of electromagnetic induction, generating an electrical current.

The power generated is produced when the magnetic field created by a fixed magnet or an electromagnet, inductor, passes through a coil, induced, placed at its center. Current induced in the coil rotating in alternating principle is continually transformed by the action of a rotary switch.

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electrical engines:

Electric motors are machines that convert electrical energy into mechanical energy absorbed electrical terminals

This is how an electric engine moves:

1. The motor (with electricity made in different ways) is fed with electricity.
2. The motor has a magnet and electrical it generates movement.

This happens because a electromagnetismlaw says that if you have electricity and a magnetic field, you have movement andviceversa.So, an engine has always magnet and a wire through which current flows by. This law makes posible to have batteries that can be filled up.
The motors can be AC (if the current flows in one way) or DC (if the currentchanges its direction). Normal engines are simple engines and reducing engines.
The first engine as we know them was created in 1712 when Thomas Newcomen built a steam machine.Some people think that engines where the water mills too.

An electric engine is composed by two main components: estator and rotor
Estator is the component which contains the magnetic field. Inside it, the rotor is composed by electric coils through which the current flows.
The interaction of magnetic field and electric current makes motion in rotor. So, electric energy will be transformed in motion.