You can easily build electric motors yourself as a demonstration model of how electricity causes movement. all you need is magnets, enameled copper wire, and a few items found in most households.
What you need:
- monopolar motor:
- One AA battery
- 1 neodymium magnets 1.5 cm diameter
- 1 neodymium magnet 1 cm diameter
- Washer 1 cm
- wire (silver solder, copper paper clip)
- electric motor:
- One AA battery
- 1 m enameled copper wire
- Copper strips from loose-leaf binders or large safety pins
- rubber band
Basic principle of electric motors
In 1820 physicists discovered that electricity creates magnetic fields. As early as 1821, Michael Faraday showed that a wire carrying a current moves in a magnetic field. The simplest electric motor was invented.
A monopolar or unipolar motor, which is called a homopolar motor in English, corresponds roughly to this motor that Faraday built. It rotates about an axis parallel to the magnetic field. To build this motor yourself, you need a few parts. A battery, some wire, neodymium magnets and a washer are enough. All things you probably have around the house.
Slightly more complex motors contain a commutator or a breaker. They rotate perpendicular to the magnetic field lines. For these motors you need a coil. This would align with the magnet and remain stationary if the circuit is not broken or reversed. You can achieve this with a commutator or the interrupter. To build such a motor you need enameled copper wire. You will also need two copper strips, a battery, tape and rubber bands
Build a monopolar motor yourself
This motor is quite simple and can be built in a few minutes. It is best to first build the motor from an empty battery. Replace with a full power source if the wire dimensions are correct.
- Place the dead AA battery with the negative pole on the larger of the two neodymium magnets.
- Place the small magnet on the positive pole and then the washer.
- Bend two bows from the wire. The beginning of the wires must be in the middle of the washer. Form the other end in a horizontal arc around the magnet that sits on the negative pole.
- As soon as you put a fresh battery in place of the empty ones, the two archwires will twist around the battery. You have a simple electric motor.
Tip: It is even easier if you attach two magnets one above the other to both poles of a lying battery and connect them with a wire bow. The battery immediately rolls away, pulling the wire bow with it.
Building instructions for a motor with a coil
This motor is a bit more complex, but also easy to build yourself. It bears a close resemblance to DC motors that you find in electric toys.
- Wrap the enameled copper wire around the battery 15 times. Start wrapping about four inches from one end, leaving four inches unwrapped at the end as well.
- Carefully pull the battery out of the wire loops and compress the loops into a flat coil (see image 1). Secure the spool with some tape.
- The small copper strips that you use to press the paper together in loose-leaf binders are suitable for connecting the coil to the battery poles. These already have holes that are suitable as bearings for the coil. If you can’t find copper strips, grab two large safety pins. Attach the parts to the battery with rubber bands as shown in picture 2.
- Glue a magnet between the two contacts on the battery. Be careful not to cause a short circuit with the magnet. He must not touch the contacts.
- Two wire ends protrude from the coil. Remove the paint from one end with sandpaper and scrape off only half of the insulation on the other end (see image 3). The remaining insulation interrupts the current.
- Put the wire in the two openings of the contacts. The coil rotates in the magnetic field as soon as you give it a quick push.
Both motors can be tinkered with simple means and show that electricity and magnetism lead to movements.