Small  generator project


Find out about our small electric generator prototype, using a single neodymium magnet and coils iron – less.


Objective: to build a small simple electric generator (pocket sized) which can generates enough power to light 230 V bulbs AC.
An electric generator is a machine that converts mechanical energy into electrical energy. It works based on principle of faraday law of electromagnetic induction. The faradays law states that whenever a conductor is placed in a varying magnetic field, EMF is induced and this induced EMF is equal to the rate of change of flux linkages. This EMF can be generated when there is either relative space or relative time variation between the conductor and magnetic field.

The generators are classified in two types :

  1. AC generators 
  2. DC generators
 How it works ?
The rotating magnetic field induces an ac voltage  in the stator windings (coil ).
The rotor’s magnetic field is produced by the neodymium magnet sphere in this case.
The permanent magnet field is constant and the terminal voltage varies directly with the speed of the dc motor.
The presented device in the rows below, is aprototype of an AC electric generator which lights up led bulbs 3W -9W, 230 V and is composed of  a coil without core (iron less –  copper wires), a permanent magnet (neodymium sphere) , a dc motor, a metal screw pot case, a plastic holder and a battery.
LED light bulbs convert AC to DC. They typically will full-wave rectify the AC and drive a sring of series-connected LEDs. They also contain a method to limit the current to the LED string.
Note :
Using  spheres with different sizes, dc motors, batteries and coils we have managed to light up a 75 W 230 V bulb
small electric generator

science projects : small generator

About generators in general :

Electric generators are devices which are using alternating magnetic fields to create a current through a wire circuit ( alternating current) AC. An electric generator converts mechanical energy into electrical energy by generating voltage (EMF) that forces electrons to flow in an electric circuit.  This is called electromagnetic induction.

Warning ! High Voltage!

How we build it :
Materials we used to build the small generator:
1.  3V Dc motor  – inside toys which using two batteries 1.5 V AA – simple generator component
3 V Dc motor small generator component

3 V Dc motor

2. coil without core inside syncronous motor 230 V – A4 laminators, microwave turntable motor – simple generator component
syncronous motor

syncronous motor

coil without core inside syncronous motor

coil without core inside syncronous motor

3. neodymium magnet sphere 12.7/13 mm 
neodymium magnet spheres

neodymium magnet spheres

4. neodymium screw pot metal case 12.7/13 mm – remove neodymium magnet from the metal case – key generator component
screw pot neodymium magnet

screw pot neodymium magnets

5. plastic conector used to fix screw pot metal case – dc motor ax inside car toys – heat the crew pot metal case to fix the plastic conector – simple generator component
plastic connector

plastic connector inside toy car

6. plastic and metal components from  mechanical construction kit – used to build the holder for  dc motor and  coil – simple generator holder

7. 3.7 V battery 600 mAh or a related battery
8. 230 V led bulb 3W – 7 W + E 27 socket 230 V 
9. power switch + wires
Operations :
we removed the plastic component from the toy car case
 we removed the magnet from the neodymium screw pot metal case
 we removed the coil from the syncronous motor
 we attached the screw pot metal case to the dc motor ax through the plastic connector
 Creating the small generator holder using the plastic kit
 Connecting the wires to the dc motor and battery through the power switch.
 Connecting the bulb using the wires to the coil output ( in Ac output it doesn’t matter the connection order, only in dc is very important),

WARNING ! we do not encourage people to replicate it !!!


the position neodymium magnet sphere 13 mm – screw pot metal case  (magnetic catch ) between magnetic poles (N and S)


electric generator neodymium sphere

position : neodymium sphere 13 mm –  screw pot metal case

We did not used magnetic materials (screws , etc ) for the simple generator holder near the neodymium sphere – it will act like a magnetic brake for the sphere.


small electric generators

small generators

small electric generator powered with 1,2 V battery lighting 3 W led bulb 230 V

small AC electric generator lighting 3 led bulbs 7 W 230 V each powered with 3,7 V battery.

The next electric generator presented in the rows below is using a neodymium magnet sphere 19 mm with a magnetic catch on an iron holder, two coils iron – less, a reed switch, two small solar panels, AC/DC circuit and a led.
Input : mini solar panels DC voltage
Output : DC voltage ( AC is transformend in DC through electronic circuit)

Changing the rotation of the sphere : reverse the polarity of the supply voltage – in this case mini solar panels.




related science projects :  fidget spinner generator page

a sciencetoolbar project

coil iron - less
neodymium magnet sphere
dc motor