What is this electromagnetic device called?

[Josh225]

What is this electromagnetic device called? I've seen a couple. There is this one: as well as one similar but you must keep the magnet in motion to generate electricity.

I would like to make one of these, but I don't know the name of it which makes it hard to search for instructions and a general overview.

Thanks!

 

[OmCheeto]

What is this electromagnetic device called? I've seen a couple. There is this one: as well as one similar but you must keep the magnet in motion to generate electricity.

I would like to make one of these, but I don't know the name of it which makes it hard to search for instructions and a general overview.

Thanks!

From the description give with the video:

Published on Jun 6, 2014
This video shows the operation of an electromagnetic induction. The coil consists of two windings of copper wire, "the primary coil 1, the secondary coil 2." The primary coil is composed of 220 turns of wire 0.40 mm. The secondary coil is composed of 120 turns of wire from 0.85 mm. The working voltage is 28-30 volts AC.
Explanation of the operation:
in the spool of wood were wrapped two coils of copper wire separate between them. When in the central hole of the spool is inserted an iron core, the coil reacts by creating an electromagnetic field. Conversely, by exchanging the terminals of the coils, the electromagnetic force is canceled at the terminals of the wires.

I would call it an "air core transformer".

 

[Delta2]

It is a transformer with removable core. When the metal core is inserted the magnetic field becomes stronger and thus it generates stronger voltage in the secondary coil.

However I am not completely sure what he is doing when we see the reverse effect, the voltage to become stronger when the core is removed...

 

[Averagesupernova]

It is a transformer with removable core. When the metal core is inserted the magnetic field becomes stronger and thus it generates stronger voltage in the secondary coil.

However I am not completely sure what he is doing when we see the reverse effect, the voltage to become stronger when the core is removed...

The windings are likely both in series with the bulb in the latter portion of the video. The bolt is drawn in with much less force.

 

[OmCheeto]

The windings are likely both in series with the bulb in the latter portion of the video. The bolt is drawn in with much less force.

Thanks!
Like Delta² , I was puzzled by the "that's not quite right" second part of the video.