What Kidn Of Wire Do You Use To Make A Dynamo
All metals contain a movable substance called 'electric charge'. Evenuncharged wires are full of charge! After all, the atoms of the metal aremade half of positively-charged protons, and half of negative electrons.Metals arespecial because their electrons don't stay connected to the metal atoms,instead they constantly fly around inside the metal and form a type ofelectric'liquid' inside the wires. All wires are full of electric fluid. Modernscientists call this liquid by the name 'electron sea' or 'electrongas,' or the 'sea of charge.'
The fluidcharge is movable, and this lets metals be electric conductors. Themovable charge-stuff is notinvisible, it actually gives metals their silvery shine. The electron gasis like a silvery fluid. Sort of.Whenever a circle of wire surrounds a magnetic field, and if themagnetic field then changes, a circular 'pressure' called Voltage appears.The faster the magnetic field changes, the larger the voltage becomes.This circular voltage trys to force the movable charges inside the wire torotate around the circle. In other words, moving magnets cause changingmagnetic fields which try to create electric currents in closed circles ofwire. A moving magnet causes a pumping action.
If the circuit is notcomplete, if there is a break, then the pumping force will cause no chargeflow. Instead, a voltage difference will appear at the ends of the wires.
But if the circuit is 'complete' or 'closed', then the magnet'spumping action can force the electrons of the coil to begin flowing. Amoving magnet can create an electric current in a closed circuit. Theeffect is called. This is a basic law of physics, and it isused by all coil/magnet electric generators.Generators don't have just one circle of wire.Suppose that many metal circles surround themoving magnet. Suppose that all the circles are connected in series toform a coil. The small voltage from each circle will add togetherto give much larger voltage.
A coil with 100 turns will have a hundredtimes more voltage than a one-turn coil.Why is this generator AC and not DC? When the magnets flip, they create apulse of voltage. But when they flip a second time, theycreate an opposite pulse? So then a spinning magnet is always makingelectric signals that go plus-minus-plus-minus? It happens because,in order to create voltage and current, a magnet pole must sweep sidewaysacross a wire. If instead it sweeps along a wire, nothing happens.In ourlittle generator here, the magnet poles don't sweep constantly along thecurve of the wire. Instead, first the north magnet pole sweeps across oneside of the coil, and at the same time the south magnet pole sweepsbackwards across the other side.
The two effects add together.But next, the magnet keeps turning around, and now the opposite polessweep across those parts of the coil. The magnet has flipped, the magnetpoles are reversed, so the coil's second pulse of voltage will bebackwards.
And if abulb is connected, then any current will be backwards too. Each time themagnet makes one complete turn, it creates a forward pulse and then abackwards pulse. Spin the magnet fast, and it makes an alternating wave:AC.If you want a DC generator, you'll have to add a special reversing switchto the magnet shaft. It's a switch called a 'commutator.' All DCgenerators have these. After every half-turn, it reverses the connectionto the coil.
That way it comes out as pulsed DC. If you look up some DIYprojects for DC generators, you'll see how to build the commutator switch.But those generators aren't Ultra Simple!
Now for the light bulb. If we connect the ends of the coil together, thenwhenever the magnet moves, the metal's charges will move and a largeelectric current will appear in the coil. The coil gets slightly warm.What if we instead connect a light bulb between the ends of the coil? Alight bulb is really just a piece of thin wire. The charges of the lightbulb's filament will be pushed along. When the charges within the copperwi re pass into the thin light bulb filament, theirspeed greatly increases.
When the charges leave the filament and moveback into the larger copper wi re, they slow downagain. Inside the narrow filament, the fast-moving charges heat the metalby a sort of electrical 'friction'. The metal filament gets so hot thatit glows.
The moving charges also heat the wi res ofthe generator a bit, but since the generator wi res areso much thicker, and since the bulb's thin filament is slowing the currentthroughout the entire coil, almost all of the heating takes place in thelight bulb filament.So, just connect a light bulb to a coil of wire, place a short powerfulmagnet in the coil, then flip the magnet fast. The faster you spin themagnet, the higher the voltage pump-force becomes, and the brighter thelight bulb lights up. The more powerful your magnet, the higher thevoltage and the brighter the bulb. And the more circles of wire in yourcoil, the higher the voltage and the brighter the bulb. In theory youshould be able to light up a normal 3V flashlight bulb, but only if youcan spin your magnets inhumanly fast.Disconnect one wire from the light bulb. Spin the magnet. Whilestill spinning the magnet, have a friend touch the wires togetherso the bulb lights up again.
Is the nail still easy to spin?Keep spinning the magnet while your friend connects and disconnectsthe bulb. Feel any differences in how hard you must spin the nail?Also try spinning the magnets while your friend connects the generatorwires directly together (with no bulb connected.)SO WHAT?When you crank the generator and make the lightbulb turn on, you areworking against electrical friction in order to create the heat and light.You can FEEL the work you perform, because whenever you connect the bulb,it suddenly gets harder to crank the generator. When you disconnect thebulb, it gets easier.Think of it like this. If you rub your hands together lightly, the skinstays cool, but if you rub your hands together hard, your skin gets hot.It takes more effort to rub skin hard so that it heats up;it takes work. And in a similar way, it's hard to heat the lightbulbfilament, it takes work. You twist the generator shaft, the generatorpushes the wire's charge through the tiny filament, and if you don't keepspinning the magnet, the magnet will be slowed quickly.FEEL THE ELECTRONSWhen your hand spins the magnets, you can feel the extra work it takesto light the bulb. Try spinning the magnets with the bulb disconnected.The magnetsbecome much harder to spin.
This happens because yourhand is connected to theflowing charge in the bulb, and when you push on it, you can feel itpush back on you! How is your hand connected to the flowing charges?Your hand twists the nail, the nail spins themagnet, the magnet pushes the invisible magnetic fields, the fieldspush the movable charges, the charges flow slowly through the lightbulb filament, and the tiny filament causes friction against the flowof charge and heats up. But then the reverse happens! The chargecan't move much because of the tiny filament, so it resists thepressure from the magnetic fields, which in turn resist the pressurefrom the magnet, which resists the twisting pressure from the nail,which resists the twisting pressure from your fingers. So, in avery real way, you can FEEL the electrons in the light bulb filament.When you push them, you can FEEL their reluctance to move throughthe narrow filament!TURN OFF THE FIELDTry changing the magnets' position.
Remove the magnets, then tape themaround the nail so that the two stacks are clinging side by side, ratherthan stacked up in a line. Spin the magnets.
Does the light bulb stilllight up? This happens because The N pole of one magnet stack isvery close to the S pole of the other, and vice versa. The magnetic fieldis now stretching between the two stacks of magnets, and isn't spreadingoutward.
Most of the field is trapped between the neighboring oppositepoles, so the field doesn't extend out through the coil. When magnets areside by side like this, they form one larger but weak magnet. On theotherhand, when you make a single stack of magnets instead, the field extendsoutwards for many inches.
The stacked magnets form a larger but verystrong magnet. If you spin the single magnet stack, thefield cuts through the wi res and pumps their electronsinto motion.MEASURE THE VOLTAGE AND CURRENTIf you can get a Digital Voltmeter or DVM, you can make some measurements.(Once you can see some numbers, you can perform some professional scienceexperiments. This is great for science fair projects.) Spin the magnetsto light up the bulb, then connect the meter leads across the light bulbconnections. Set the meter for AC volts. Spin the magnets and see justhow high a voltage your generator produces.How high can you make the voltage justby using fingers?
Or using a hand drill? Try spinning the magnets justfast enough to barely light the bulb in a dark room. How small a voltageis needed? Also trydisconnecting thelight bulb, then measure the AC voltage across the two ends of the coil.Can you tell if it's still the same as when the bulb was connected?
Hint:to spin the magnets at a constant rate, use an electric drill with afully-charged battery. Or perhaps hook the nail to an electric motor andconnect the motor to a DC power supply with settable voltage.Note: The light bulb has around 50 ohms resistance.
Also, 250ft of #30wire has around. Because of the wire resistance, thegenerator can only create around 60 milliamps current at most (0.06amperes.) If you wind extra #30 wire onto the generator, it will increasethe maximum voltage, and maximum power. But since this adds moreresistance it WON'T increase the maximum possible current.
To increasethe maximum possible current, either replace the #30 wire with thickerwire, spin the magnets faster, or use a stronger type of magnet material.There is a simple way to convert your generator into amotor. It involves using paint or tape to insulate a spot on one side ofthe nail,then using a 6V battery and using the generator's wires,touching the nail to form a switch. The rotating magnets turn the nail,which turns the coil onand off at just the right times. Can you discover the trick?MAKING DCYou can change this generator so it makes DC rather than AC.
The voltageis still very low, so it's not very useful. If spun very fast, you mightbe able to recharge a tiny 1.2v rechargeable battery. (Maybe you couldadd lots more turns of wire to the coil to increase the voltage?)Converting to DC:The hard way: add a spinning 'commutator' switch andsliding metal 'brushes,' so that each time the magnets turn half way, theswitch reverses the generator connections.Easy way: Add a one-way valve! An 'electricity valve' is called a diodeor rectifier.
If you connect a diode in series with one of your motorwi res, it willonly let the charges flow in one direction. It will change theAlternating Current into one-way flow (called 'pulsating direct current.)Try diodes from Radio Shack such as 1N4000 or 1N4001. Unfortunately adiode needs about 3/4 volts to force any charges through, and this voltagesubtracts from your generator output. If your generator only puts out onevolt, then the diode will reduce this to 1/4 volt.
So if you want to adda diode, try doubling or tripling the amount of wire onyour generator. Also try using a special 'Schottky' diode with lowervoltage than 0.7V, such as 1N5819 fromHISTORY OF 'ULTRA SIMPLE' GENERATORSeeWhile running the tech shop at the Museum of Science in Boston, I wasworking on new ideas for exhibits for the Electricity Hall in 1988. Iknew that the Exploratorium had an electric generator exhibit where themuseum visitor would yank a plastic-embedded coil-plate through a row ofhuge magnets (large magnetron horn-magnets from WWII military radar.)Doing thiswould light up a small bulb.
I just knew that there hadto be some method whichuses less expensive, common magnets. So I stacked up a pile of 3'loudspeakermagnets (those black donut things) and waved it past various coils.Finally I wound about five pounds of #26 wire around a ring of nailspounded into a board, hooked up a #49 light bulb, then moved the stack ofspeaker magnets in and out. This easily lit up the bulb.Around 1994 I was thinking about the ultra-simple electric motor whichlater became known on internet as the 'Beakman Motor.'
Wouldn't it becool if kids could also make an electric generator just as simple?But it needs be done using parts from a Radio Shack store, sinceRadio Shack had the special light bulb as well as magnets and spools ofelectromagnet wire. After a few hours of experimenting I fould that Icould just barely light up the 20 milliamps bulb by using a single spoolof #30 wire from radio shack. But the wire had to be VERY close to a fastspinning magnet, and the magnet had to be composed of four powerfulceramic magnets in a stack.To impress all the Physics Teachers, I tried to make the parts be easilyavailable, and the cost as low as possible. To make a popular project, Imade sure no tools were needed except scissors. I refused to use ballbearings or saw-cut plastic parts.
So I made my own cardboard box for thecoil, and used a nail for the spinning shaft. To avoid extra parts, thenail is just clamped by the powerful magnets. Here's a challenge: try tolight a bulb, but do it with a generator which is even simpler.Want a much more powerful motor or generator? Those need stamped-outiron sheets for laminations.
But there's another way. Look into Edison'stactic: he took the, modified it byand sold them like hotcakes.The magnetic core, the 'laminations' of a Gramme rotor can be made from along length ofiron wire wrapped as a hoop and doused with epoxy, tar, etc. I don't knowif fine iron wire is easy to find, but barbed wire and hay baling wire iscommon. Wrap heavy copper wire around the entire iron ring and mount iton a flywheel. Grind the outer rim flat, so the copper spiral can become itsown commutator. The stator can be permanent magnets, or non-laminatedsolid iron blocks, since it's DC. Early versions used 'paintbrushes'made of fine iron wire as the brushes, later replaced with blocks ofslippery graphite.But then go and do as Tesla did, and convert your initial stator designsinto a compact cylinder shape with enclosed coils, rather than using hugelong horseshoe-magnets like Edison'sdesign.Motor Triva: electric motors were mereuntil Zenobe Grammedeveloped a generator which was intended to replace battery banks, sinceit gave extremely smooth DC output voltage.
How Does A Dynamo Work
During an inventors show, anassistantup to another that was running under steam power. The second one ran as amotor, as a.hundreds horsepower. motor.
That moment was the start of theelectrical age in industry. But this breakthrough is not much mentionedin American Textbooks, perhaps because it would make Thomas Edison appearless of a genius.WARNING: Keep the magnets away from computers, disks, videotapes, colorTV sets, and wallets and purses containing credit cards. Try this: Keepthe generator far from your color TV, turn on the TV, start spinning thenail so the magnet is spinning fast, then bring the generator about 2ftaway from the TV screen. DON'T BRING IT CLOSER!!! Keep spinning themagnets, and you'll see a cool wobbling effect in the TV picture, alongwith some color changes. The field from the magnet is bending theelectron beam that paints the picture on the screen.
Be careful, if youbring the magnet about 15cm away, the iron sheet inside the TV picturetube will become magnetized and the distorted colors will be permanent.NEXT:(PREV: )Want books? Try searching:(try 'science fair project' keywords too)See:Created and maintained by.Mail me at:.
Now take a magnet keep it almost 3-5 cm away from the nails head.now star to move it in various ways.at one time in a certain type of move the bulb will start to glow.here i have shown circular movement.then any time you may light it with that move.ifit does not work then try by changing the poles of led.i am sure that it is a project that may give you a first prize in science fair. If i make any mistake inenglish forgive me because i am from a non -english speakin coutry.i am argha halder from naogaon bangladesh.i study in class 7 in biam laboratory school naogaon.