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## Creating large DC Motor for Funzies. Won't work.

 Quote by Flyingwing12 When you think of series are you thinking of this? It seems as if the lamp is acting like a resistor?
Yes, the lamp is a convenient resistor. I suggested that you use it so it limits the current through the strand of thin wire. If you just connect a piece of wire across a car battery there will be a big spark, the wire will glow red hot and melt, thus ending the experiment. But with the lamp in series, the lamp will limit the current to a safer level. The wire may still get hot and start smoking, but the experiment will have served its purpose: do you see instant movement in that strand of wire or not?

You must take the eggbeater out of the circuit for this single wire test so it doesn't steal the current from the piece of wire. Use a strand of wire that is flexible and hang it so it is free to move a bit, so that you can watch for movement. Because if you observe that the single strand does not move, then sure as anything neither will your eggbeater rotor!
 You really need a commutator. Suppose with a single loop of wire the current is split evenly through the upper and lower loop. In order for the rotor to turn the upper wire has to move in the opposite direction of the lower wire. One wire will fight the other. Remember the right hand rule when it comes to magnetism and current flow? The reason your single loop worked at all is because the field was small enough on the top compared to the bottom so the lower 'outpulled' the upper.

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 Quote by Flyingwing12 I proved today that a single wind of magnetic wire works. I was able to make a small 3 inch diameter circle out of mag. wire and make it rotate with 9v and the same support setup as the larger motor .
I think you mean "it rotated a few degrees then stopped" don't you? It surely didn't keep turning and turning endlessly?
 Tried hooking up the "eggbeater" to a 12v supply and it melted the wires.
So it melted the plastic-coated wires from the battery, or did it melt the egg-beater wires? (They look so thick that I'm surprised the 12v supply survived. Your eggbeater is no different from a short circuit.)
 Is there a formula I can use to determine the strength of a magnet that I need to get this " Eggbeater" to work. I know it is possible. It has to be.
Even if it is theoretically possible to get your homemade rotor to operate, it will first have to be modified a bit to give it commutator action. But I'm not suggesting you do that until we establish whether it stands any chance of working.
 I got the small single wound job to spin continuously yes. It has to be possible for this thing to spin. I think I just need a very strong magnet. And how would this commutator work? This keeps being mentioned and yet no one says how I should hook it up? try using MS paint to make a diagram or something like that. They help out a lot.
 And electric motors of this scale are basically short circuits right? I thought the huge coils of non conductive wire are for resistance? Please elaborate.

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 Quote by Flyingwing12 And electric motors of this scale are basically short circuits right?
Well, "short circuit" is a relative term. To a 12v car battery, your eggbeater with its heavy gauge copper wire is getting close to a short circuit. Connected directly to the battery terminals I'd expect the wires to glow red hot and melt, that is, if the battery didn't explode under the strain.
 I thought the huge coils of non conductive wire are for resistance?
It's called "insulated copper wire" because the outside is covered with an insulating layer, either enamel varnish, or coloured plastic. Motors use lots of coils to produce strong magnetic fields.

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 Quote by Flyingwing12 I got the small single wound job to spin continuously yes.
Great! Then why not settle for that as your demo motor? It's so unusual that most people will be mystified to see it spinning, telling you it can't be happening—it won't spin without a commutator.

If you go to youtube.com and search for "simple motor" you will see plenty of DIY motors. You might get ideas from there. But I really think you should stay with the simple one that spins once you have got it going!

I once salvaged the electric motor from the windshield wiper assembly I found in an old car dump on the edge of a wood. The assembly was mounted at the top of the windshield, and the armature of the rotor projected through the case (as a brass rod) so it was within reach of the driver. You see, the motor was a design that isn't always self-starting, so it was sometimes necessary to twirl that rod to get the wiper's motor to start spinning!

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 Quote by NascentOxygen It's so unusual that most people will be mystified to see it spinning, telling you it can't be happening—it won't spin without a commutator.

Anyway,

 Recognitions: Gold Member dlgoff, I don't think Commuter is needed for a half-turn configuration in a non-uniform Magnetic field. (The OP's setup.) The videos and documents you are discussing refers to a regular DC motor with uniform fields and integral no. of turns, which surely does need commutator.
 Recognitions: Gold Member To prove my concept, I tried to do this quick and dirty experiment, but it failed. My guess was, While the wire is in lower half of its imaginary rotation-circle, the torque will be produced in one direction and when it is in top half, torque will be in opposite direction. But since the average Magnetic field strength on top half is lower than in bottom half, during each complete rotation torque should be +ve and hence, the rotation should have continued indefinitely. I think, the inertia (due to torque in bottom half) isn't being able to overcome -ve torque + friction during the top half. i.e. I think the reason for failure is mechanical problems. If I have some serious theory flaw, please let me know. P.S: I do believe that coil design with commutator would surely give the best result (an order of magnitude more torque), but I am just trying to verify if other method could work* or not. *Although for demonstration purpose only

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 Quote by I_am_learning dlgoff, I don't think Commuter is needed for a half-turn configuration in a non-uniform Magnetic field. (The OP's setup.) The videos and documents you are discussing refers to a regular DC motor with uniform fields and integral no. of turns, which surely does need commutator.
You are correct however giving the OP a little more info about motors could help his/her learning.
 I had a car battery charger hooked to the motor and was only getting 9 volts out of it. This was until I moved the motor and it made contact, in which the wires were instantly fried! What caused the voltage to be 9 volts across the pos/neg wires?

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 Quote by Flyingwing12 I had a car battery charger hooked to the motor and was only getting 9 volts out of it. This was until I moved the motor and it made contact, in which the wires were instantly fried! What caused the voltage to be 9 volts across the pos/neg wires?
I guess you are implying it to be a 12 volt charger? Possibly the charger is not much more than a transformer with a full wave rectifier. Suppose you supplied a full wave rectifier with a 14v (peak) sinewave.... neglecting losses, the output would be a series of half-sinusoids of peak amplitude 14v. If you use calculus (or a good ol' moving-coil meter), you will discover that the average of this rectified sinusoid is 9 volts. For a short time around the peaks a 14v sinusoid overcomes the car battery voltage, and forces charging current into the battery in short bursts.

I suggest that you continue to use a headlight globe in series with the charger during your experiments. This should protect the charger from damage due to overload. If your experimental motor shows no sign of working when the charger has a globe in series with it, then it's a safe bet it won't have worked had you overloaded the charger.

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 Quote by Flyingwing12 I had a car battery charger hooked to the motor and was only getting 9 volts out of it. This was until I moved the motor and it made contact, in which the wires were instantly fried!
Which wires melted? The wires coming from the charger, or the wires you soldered together to make the eggbeater?

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 Quote by I_am_learning To prove my concept, I tried to do this quick and dirty experiment, but it failed.
By failed do you mean there was no observable movement? What is the material in that catenary? It looks a lot like polycarbonate string.

Are you doing the test that I suggested OP should try?
 Recognitions: Gold Member its working now. http://www.youtube.com/watch?v=D1Gpg...e_gdata_player

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 Quote by I_am_learning its working now. http://www.youtube.com/watch?v=D1Gpg...e_gdata_player
Well done, I_am_learning! That's a convincing demonstration.

If you soldered (or twisted) another semicircular piece onto that, to complete the ring, it should spin faster and more smoothly. Current drain will go up, though.