Introduction: Be a Scientist: Build an Electrostatic Motor

Picture of Be a Scientist: Build an Electrostatic Motor
Normal motors are driven by electromagnetic forces. This motor needs no batteries, mains supply or solar cells. Electrostatic motors are turned by the kind of electricity generated by wearing nylon clothes in a modern office. Think of it as gigantic nano-technology as well, because this is how the microscopic motors of nanobots work.

Step 1: Gather Your Materials.

Picture of Gather Your Materials.

For the basic motor, you need a disposable plastic drinking cup, aluminium foil, glue-stick, bamboo or dowel (at least a centimetre or two longer than the cup is tall), wire and a non-conducting base, such as a plastic plate or a wooden board.

Step 2: Making the Rotor.

Picture of Making the Rotor.

The spinning part of any motor is called the rotor (because it rotates).

Cut three pieces of foil. The exact dimensions for the basic motor are not important, but they need to be slightly shorter than the cup is tall, and of a width so that there is a gap of about 1cm between the pieces when you stick them to the cup.

Stick the pieces of foil to the cup. Space them evenly around the cup, and make sure there is no point where neighbouring pieces touch each other.

(I say "three pieces of foil", but the exact number seems unimportant - maybe somebody would like to research this point - as long as it is two or more.)

Step 3: Making the Base and Adding the Rotor.

Picture of Making the Base and Adding the Rotor.

Sharpen the bamboo or dowel to a reasonable point, and then use the blu-tac to stand it in the middle of the base-board. Balance the cup (upside-down) on the bamboo so that it spins freely.

It is possible to sharpen the dowel with a pencil sharpener, or even use a sharp pencil instead of the dowel. Bamboo usually needs a sharp knife.

Step 4: Making the Connections.

Picture of Making the Connections.

Cut two pieces of wire. They need to be long enough to reach your source of static electricity and your earth connection. If you are using balloons to generate the static, give enough clear air between the balloon end of the wire and the motor to prevent draughts from the balloon knocking the cup off its perch.

Position the wires so they stand each side of the cup. They should be about 1cm from the cup (they MUST NOT touch the rotor), pointing at the cup. Fasten the wire in place (how you do this depends on the nature of your base - blobs of blu-tac, drawing-pins, sticky tape, it does not really matter).

Your motor is now finished.

Step 5: Running the Motor.

Connect one wire to connect to a good Earth point - any bare metal part of the home plumbing system is good. If all your water pipes are plastic, poke the wire into th cold-water tap and let it trickle slowly. For your own safety, do not connect the motor to any part of your mains electrical supply.

Now you need a source of static electricity:

If you are lucky enough to own a Van der Graff generator (or you have made your own!), that would be perfect. The earth wire can be connected to the bottom dome of the generator. Otherwise, anything that generates static will do. Inflate a long balloon, rub it on your sweater, and then gently stroke its length down the end of the wire not connected to the Earth. Repeat. Gather several friends, also with balloons, and take turns to add charge to the machine. Lay a sheet of aluminium foil over the screen of a TV or monitor that crackles a lot when you switch it on and off, and use wire to connect the foil to your motor. The more static you can supply, the faster your motor will run. We ran six motors simultaneously from my Van der Graff generator.

Step 6: How It Works.

As you add charge to the unconnected end of the machine, it is transferred to the piece of foil nearest to you, giving it the same charge as the balloons. Like charges repel, so the foil is pushed away from the wire. This turns the rotor.

When the rotor turns, it brings the next piece of foil to collect charge, and also moves the first piece towards the earth connection to discharge. The whole process repeats for as long as you supply charge to the motor. The only real limiters to the speed are balance - wobbly rotors will turn more slowly - and friction. The top speed of your motor will be controlled by friction on the balance point (so make it small and slippery, but don't use grease, try graphite) and by air friction on the cup (so try not to have too many wrinkles or loose edges).


krueger5373 (author)2017-10-11

im making thing for a school project. would a van de graff work for the charge. and should i glue the tin foil on pr just have it stick by its self

Kiteman (author)krueger53732017-10-28

A VdG would be brilliant, and yes you will need to glue the foil on.

knightscode27 (author)2015-03-25

Gonna make this!!

Kiteman (author)knightscode272015-03-25

Post pictures when you do!

science mad (author)2015-01-08


Kiteman (author)science mad2015-01-09

Isn't it just?

chasebh89 (author)2013-07-27

no... why is it important it sticks? its most likely a bad ground but i tried it on the faucet and still no success

Kiteman (author)chasebh892013-07-28

It means that you are either not generating much charge when you rub it, or the air is humid and the charge is leaking away too quickly - try again on a dry day.

chasebh89 (author)2013-07-27

mine wont work :/ did everything correct and am powering it with a balloon (my leyden jar won't charge)

Kiteman (author)chasebh892013-07-27

There are many things that could be wrong, but the most likely are excess humidity letting charge leak too easily, or a poor Earth ("ground") connection.

Will your balloon stick easily to a wall after you rub it on something?

chasebh89 (author)2013-07-27

i did everything you said to do and it wont work :( i power it by balloon and put the ground in the faucet but it wont turn... help?

SgBriggs (author)2013-01-06

could i power this from a bank on capasitors?

Kiteman (author)SgBriggs2013-01-06

Not very well - the voltage needs to be in the thousands.

john500 (author)2012-09-23

i have a question, one part of copper wire goes connected to earth and to a static electricity fuel or to a baloon, the other part of wire... goes where?

Kiteman (author)john5002012-09-23

That's it. One wire feeds static from the generator (balloon, whatever), and the other drains it to Earth / ground.

ThatCatMan (author)2012-09-08

Are we able to use things other than a plastic cup, say a lightweight tin can with a curved bottom?

Kiteman (author)ThatCatMan2012-09-09

Not for the rotor - each panel of foil needs to be fully insulated from the others. You could use a paper cup, or a plastic bottle, but not a metal container.

brettbeatty (author)2012-02-10

As I understand, the number of foil parts on the rotor should be an odd number so the charges are never in equilibrium.

Kiteman (author)brettbeatty2012-02-11

That's sound logic, although I've never tested it.

We tended to make the foils in pairs to make it easier to balance the rotor.

NineInchNachos (author)2006-01-13

This looks like a fun project. Can't wait to try it out; Thanks for the post!

Kiteman (author)NineInchNachos2006-01-13

A pleasure. I'm trying to work out how to attach a video of it running.

GorillazMiko (author)Kiteman2008-06-12

Kiteman's first comment...

Doctor What (author)GorillazMiko2010-01-16

 So I see I'm not the only one who tried to find Kiteman's first comment.

dombeef (author)Doctor What2011-07-19

Same here...

theburn7 (author)Kiteman2008-06-13

WOW i am replying on kiteman's first comment, i feel with great gratitude

StyleCore (author)Kiteman2008-06-12

Kites first comment?

jembersonic (author)2011-05-15

This didn't work With the TV method, my ground was a plumbed radiator :/

Kiteman (author)jembersonic2011-05-15

That's a shame.

My first questions would be "Was the weather humid?", and "Were you in contact with bare metal on the radiator?".

Ugifer (author)2011-04-06

This is great - thanks for the instructable.

I bought a cheap refurb Van de Graaff off e-bay and it arrived today. The thing is, the generator makes so much electrostatic wind that a plain plastic cup will turn in any case - no need for the foil!

I made my rotor using mylar film from a crisp-bag (chip-bag if you are American) and it seemed to work very well. Turned when the other end of the wire was about a foot from the VdeG. No need to actually contact the dome.

Kiteman (author)Ugifer2011-04-06

Wow - how big is your VdG??

Ugifer (author)Kiteman2011-04-06

Nothing huge - dome is about 9". Makes maybe a 3" spark.

I think the friction on the cup is just so low that it turns with the slightest breath. Certainly you don't need to be anywhere near contacting the dome once its charged up to make it spin (that's the rotor with the mylar strips). It wil easily turn a plain cup by the wind it produces, but you need to contact the dome for that one.

Electroinnovation (author)2010-04-10

I just recently built something like this...and unfortunatly it is hard for me to find somewhere to ground my wire near my old tv. Would it be possible to build a sort of leyden jar or something to store the electricity then discharge the jar to my house plumbing later?

You really need a decent "ground" for this to work.

If you only have a couple of feet of spare wire, find an extension lead.  Touch the plug end to your ground, and stick the spare wire into the socket end at your motor.

You could, though, charge the jar and then use it to run the motor...

matstermind (author)Kiteman2010-08-30

great way to accidentally electrocute yourself :D

Kiteman (author)matstermind2010-08-30

The VdG is much more fun.

matstermind (author)Kiteman2010-08-30


ohh ok thanks

rrpo_10 (author)2010-03-11

this is very hard i am electriacally shocked 5 times and still i can't make the rotor move....can you help me out??--- i use my tv and a foil and on the other part i use cold water with salt....yet it,s revolves but it is not continous....aarrgghhh this one is killing me!!!...pls help me guys

Kiteman (author)rrpo_102010-03-12

The cold water with salt is the problem.

Connect the the Earth (or "ground") instead.  Use a longer wire and touch it to bare metal on a cold-water pipe.  The container of water will charge up, but not allow that charge to flow away.  When it is as charged as the TV, the static will stop flowing, and the motor will stop.

magicmike5462 (author)2010-02-18

where do i connect the earth to

Kiteman (author)magicmike54622010-02-18

See Step 5 - any bare metal that is connected to the ground.  Plumbing is good.

azuro (author)2010-01-30

Neat work I must say.

Kiteman (author)azuro2010-01-30

Thank you.

impedance214 (author)2009-10-05

hey i try to used the tv as a source of static but it did not work.. do i need to cover large part of the screen to collect more static?

bears0 (author)impedance2142010-01-09

 it cant be plasma or flatscreen it has to be the big old tvs and the bigger the better

just in case you didnt know


Kiteman (author)impedance2142009-10-05

Yes, that would help.

skatepark13 (author)2009-01-31

thanks for the help very neat

Kiteman (author)skatepark132009-02-01

You're welcome.

octavian234 (author)Kiteman2009-12-20

Kiteman is awesome!

Kiteman (author)octavian2342009-12-20

Thank you!

About This Instructable




Bio: The answer is "lasers", now, what was the question? If you need help, feel free to contact me. Project previews on Tumblr & Twitter: @KitemanX
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