Creating an electrostatic motor is easy enough to do – as long as you have the right materials. And when it comes to making motors, did you know that you can make them out of soda bottles?
The key is to make sure that you are able to replicate the attraction and repulsion of an electric charge – which is the characteristic of an electrostatic motor. This type of motor also requires a high voltage supply of power so this is an important consideration when you are creating electrostatic motors using soda bottles.
What you will need:
- 3 2-liter pop bottles – with 1 plastic cap
- Roll of aluminium foil
- Rubber cement
- Silicone caulk
- 13” wooden rod (1/8 in diameter)
- Short sheet-rock screw
- Small Phillips-head screw
- 2 8” pieces of solid copper wire (e.e. coat hanger)
- Wood plank for the base – can be metal or plastic
- Duct tape
- Hookup wire to attach the power supply
What you need to do:
Preparing the wooden rod:
- Cut the wooden rod up to a length that is 1 inch longer than the middle bottle. Screw a small Phillips-head screw into the tip.
- Drill a hole right in the center of the plank. The hole should be smaller in diameter than the rod.
- Take the unsharpened end of the rod and force it into the hole in the plank.
Making the rotor bottle:
- Take the middle bottle and drill a hole in the exact center of its bottom. This hole should be slightly bigger in diameter than the rod.
- Slide the sharpened end of the rod. Check that the bottle can spin freely. If not, make the hole slightly bigger. Be careful not to make it too big to keep the bottle from rattling around when spinning.
- Take the plastic cap and screw the short sheet-rock screw through – with the point extending downwards in the bottle.
- Assemble the bottle and the wooden rod – making sure that the point of the sheet-rock screw will ride in the head of the Phillips-head screw on top of the wooden rod.
- Take the aluminium foil and cut it into three broad strips. Measure it against the center bottle in such a way that it is wide enough to cover the flat part (see illustration).
- Use the foil to cover the circumference of the bottles and leave a ½ inch gap between each foil.
- Cut the corners of the foil so they are curved instead of edged.
- Glue the foil on the bottle with rubber cement.
- Coat both the bottle and the foil, let it dry for a while and then glue it together.
- Place the foil so it is not touching each other – be mindful of the ½” vertical gap between each foiled section.
Making the 2 “stator” bottles:
- Get the two remaining bottles and glue a large sheet of foil on each bottle.
- Leave 2 inches at the bottom without foil. Make sure the foil is not touching the base or the duct tape that might be used to secure it to the base.
Making the commutator “brush” wires:
- Get the commutator – the heavy wire or the coat hanger that is cut into 8-inch pieces.
- Attach it to the stator bottle so the ends are near the rotor bottle surface (but not touching it).
- Bend the tip so it is pointing to the surface of the rotor bottle (see illustration).
- Curve the end of the wire into an S-shape to maximize the contact with the foil on the stator bottle.
- Embed part of the S-shape using silicone caulk on the foil bottle – be careful not to insulate it because the foil of the stator bottle and commutator wire should be electrically connected to the power supply terminal.
- Bend the short ends of the S-shape when the glue sets so it will be in solid contact with the foil of the stator bottle.
Assembling the stator bottle:
- Assemble the bottles so they are spaced ½” from the either side of the rotor bottle.
- Use duct tape to secure them in place – be careful not to touch the foil.
Fixing the bearing:
- Check the rotor bottle and make sure it spins freely with the screws attached to the plastic cap and wooden rod keeping it in place. This bearing should help make the bottle turn with just the slightest air.
Testing the motor:
Attach this motor to a power source that can supply 5,000 volts. These are what can be used.
- Negative ion generator (can run off a 9v battery)
- Aluminum foil on a TV screen (a bit dangerous)
- Large electrophorus
- High voltage DC supply
The power supply should have 2 output terminals. The positive lead is connected to one stator bottle’s foil and commutator wire while the negative is connected to the other bottle.
In case there is only one output wire, this usually means the missing wire is internally connected to the ground. Connect the output wire in one bottle as instructed. The other should be connected to the electrical ground through the use of a metal faucet, sink or even a metal screw that can be found on the cover plate of an electrical outlet or light switch. A few feet of aluminium foil on the floor can even work.
What just happened:
The high voltage applied to the foil of the two stator bottles will create two charge imbalances, one positive and one negative. This causes a tiny spark to jump from the tip of the commutator brush to the foil sector of the rotor bottle. The foil sector that is touched by the positive commutator will become positive while the same happens to the sector touched by the negative commutator. Since the charges from both the commutator and the foil sector under it are alike, they will repel eat other and that will cause the rotor bottle to move. This movement will cause the commutator to touch a new sector and the process will repeat – thus keeping the rotor bottle rotating.
As the force is applied continuously, the speed of the bottle should rise higher. It will soon stabilize because of external factors like the air, bearing resistance, etc.
