what  is the physics of creating low speed electric (ac) alternator and how low can it get?
404423
A simple AC electric generator simply involved rotating a magnet inside a coil, or rotating a rectangular coil inside a magnetic field (which is a little trickier requiring conducting rings at the ends of the coil and carbon brushes to connect the rotating coil to the external circuit).\n\nAs the coils pass through the magnetic field, the current induced is proportional to the strength of the magnetic field, the speed at which the coil passes through the field, and the area of the coil, and the number of turns in the coil.\n\nThe maximum electromotive force generated in each turn of the coil, (essentially, the voltage amplitude of the AC current produced), is given by:\n\nEMF = NBAw\n\nN = number of turns in coil\nB = magnetic field\nA = area of coil\nw = angular frequency of coil = 2 pi / T  \n(T = period)\n\n A single loop of wire passing slowly thought a weak magnetic field will produce the lowest possible current, which will appear alternating pulses if measurable at all. Increasing the contributing factors slowly will allow you to find the threshold at which AC current can be detected.
808544
Man did u luck out running into me, go to www.sciplus.com "American science and surplus", all sorts of abandon science projects, factory over runs, cancelled government orders, motors, solar cells, weird stuff in the science dept, it's a mad doctors dream come true, CHEAP TOO ! check it out, you'll find lots of "COOL" stuff, that has many uses ! I did a hydro-electric demonstration of power application, that was so small, I could do it in a lab sink, E-mail me if you want an "A", it's an easy experiment, inexpensive, looks very sophisticated, yet simply displays the hydro-electric properties of producing low cost, hydro-electric power, using no battery's or electric for assistance, just water, so it's completely SAFE ! works on displaying milli-amps of D.C. power, yet you are still producing (at a very low voltage) power.
926049
http://en.wikipedia.org/wiki/Electric_motors\nAre you talking hobby motors? There are many different types of electric motors: all of which "brake" or slow down differently.
362726
my dear, hope u r big enough to under stand my answer.\nok i appreciate ur idea to conserve all the mechanical energy produced in a car, but the problem is c if the battery can run a car which requires 100w power that means the power delivered by the battery is 100w now that power is exactly sufficient to run the car but if u want to recharge the battery again u need 100w of more power which will increase the load on the same battery which is to be recharged. which is absurd. so my dear it is practically IMPOSSIBLE to manufacture a car of ur kind. hope u got my answer if u dint understand u go through it once again then also if u face problems do not hesitate to write to me ok bye.
914175
Depending on the size of the Battery. Find an electric motor that use the same voltage and connect an outside source to turn it. Motors work on the same principle as a generator (To be simple about this). If, you apply voltage to the motor it will turn, if, you turn the motor in some way; it produce voltage. You can test what I say with window fans. Take two and face them toward each other. Turn on on high and it will make the other fan turn. Take an AC volt meter and measure the voltage at the plug of the fan that being turned. The faster you can make the fan turn the better your output voltage. This work the same with a little electric motor for your generator. If, it run on 12 volts DC then it will output the same, if, it turned fast enough and actually charge a battery. Hope this enough to help.
313818
An spinning alternator produces alternating current. After each half cycle, the opposite side of the coil passes through the same magnetic field. As the coil passes through the magnetic field, current always flows in the same direction, but the coil keeps flipping, so the result is alternating current. \n\nIn the case of a car alternator, its intention is charge the battery, which requires direct current. The diode only allows current to flow in one direction, converting the AC into DC, which can be used to charge the battery. \n\nIf the diode goes open ciruit, then no current will flow at all. If the diode goes short circuit, it will allow AC to flow, which will not charge a battery and can cause damage.
537140
Think of it this way.  Your car will slow down if I drop an elephant in your trunk while your driving.  \nA high load drags the voltage down.  \nThe power supply can't keep up with the amount of energy the load is wanting.
971626
Your question isn't clear.\n\nI suspect that what you mean is "how low can I go before I can't do what I want to with the motor".\n\nDepending on the inverter manufacturer, a typical limit is around 7 hertz. This is because reducing the frequency much lower will cause feedback issues and overheating (due to harmonics) in the drive. Also possible is the cycling frequency of the thyristors.\n\nMost applications will prefer low-end frequencies in excess of 12 hertz - to avoid possible tuning/torsional amplification with the structure to which the motor is mounted. No sense trying to run right on a structural resonance point!\n\nPracitacally speaking, there's also an upper limit on frequency as well, usually imposed by the motor design. Often, this is approximately at 2.2 times line frequency (133 hertz for 60 hertz systems, 110 hertz for 50 hertz systems).
616514
Generating static electricity.
152613
How it works\nThe Van de Graaff generator is powered by a high speed electric motor. It has a belt running on two pulleys. The lower pulley is made of an insulating material and the upper pulley is made of metal. There is a grounded comb close to the belt in front of the lower pulley, and another inside the terminal, close to the belt in front of the upper pulley, connected to the terminal.\n\nAdhesion between the belt and the lower pulley charges the pulley, and it attracts opposite charges to the outer surface of the belt from the grounded comb. The belt then transports these charges to the terminal, where they are collected by the upper comb and transferred to the terminal. The shielding provided by the terminal allows the continuation of the process even if the terminal is already strongly charged. The high speed of the belt, along with the large discharge electrode, allows the continuous buildup of charges and great voltages to be achieved.
165215
High speed Electrical Car, which can reach the speed of 370 KM/H
378761
400 Hz transformers, motors and generators are always smaller and lighter than their 60 Hz equivalents. The motors and generators use lower-inductance windings and tend to operate at higher rpms and lower torques. However, according to the ref., this weight savings comes at the cost of lower efficiency due to greater wiring inductive loss at higher frequency.
1121007
yes. electricity flows one direction,comes to a stop, then flows in the  other direction. the alternator pushes the electrons in one direction for 1/120 of a sec.then the other direction for the same amt. of time.( for 60 cycle current ) one direction is the pos.1/2 cycle the other is the neg. 1/2 cycle.  the zero crossing point is the instant between one direction and the next, when current flow is stopped.
726624
A bicycle seems like a good base. If you connect it to a automotive alternator and 12v battery you can produce and store power using cheap available items.\n\nIf you want 220 volts, you can buy inverters that produce it from a 12v battery, again using "off the shelf" equipment.\n\nHappy cycling cause I think you are going to find the human body quite limited at power production.\n\nps, To build something using the items I suggest would mean supporting the bicycle, hopefully you could use the wheel as a pulley without its tire and drive the alternator (having the gears of a standard bicycle being better than an exercise bike to try and match the ratio you need) Since we're not talking much power, the drive belt wouldn't need to be too technical but you may want to change the pulley on the alternator to something wider to match the wheel. If your bicycle support is bolted to a piece of plywood laying on the floor, you should be able to bracket the alternator to that plywood and keep the belt tight enough.\n\nThe electrical connection is fairly simple, connect the big lug on the alternator to the car battery +ive and the casing to the -ive. You will need to connect a small indication light between the small lug and the +ive as this is part of the charge circuit. I suggest a ammeter in the circuit to prove the doubting people on here they are wrong and that you can drive a charge current into the battery but don't buy one with too big of a range :-)\n\npps Try to select a low power alternator (off a small car). \n\nppps If you want to do this without incurring a large expense, you need to make best use of parts that are readily available and do the engineering to suit. If this is not your best subject, you may need to seriously consider whether you want to waste any time any money attempting it.
928978
It wouldn't be easy.\n\nPower supplies for PC's generally produce four outputs: +12v, -12v, +5v, and -5v. Some PC power supplies also produce +3.3v and -3.3v. These voltages are measured with respect to a ground of 0 v. \n\nYour car battery is probably 12v, which means that there is a total of 12v of potential between the + and - poles; so the cathode of your car battery gives -6v and the anode gives +6v with respect to ground. It's very easy to step these voltages down to +-5v and +-3.3v, just put the appropriate resistor into the circuit and there you are. \n\nBut stepping the voltage UP to +-12v is another matter entirely. For that, you will need a transformer of the correct size and winding. Further, you should be aware that most desktop PC's want to consume 100, 200 or even 300 watts, which may easily be more continuous power than your auto battery is designed to give.
117649
DC series wound motors and generators are the same thing. One you apply mechanical power to and you will get a rippled DC wave form out. The more commutator bars (or magnets) there are the less ripple you get.\nAlternators (generators) are like you find on a car and in the generator sets that power the world. They have rings that go all the way ring the armature instead of the slits in commutators. This means that as the armature spins through the fields of the magnetic an alternating current is induced through the winding and out through the two rings. This is better for the transmission of power over distances rather than DC. So two rings are single phase, three rings are three phase. \nThe difference in a car is that after the AC is produced a set of diodes rectify the current and then a regulator levels it to 13.8volts DC cause batteries dont like AC.
583473
Pretty simple. If you are going to employ a variable frequency drive or inverter to vary the motor speed you must then select an inverter duty motor. The reason is because motors are designed to cool themselves while running. Conventional motors are designed to dissipate heat at full speed (60 Hz). If a conventional motor ran at lower speeds then eventually it would get too hot causing insulation breakdown and then.....bad things happen. \n\nInverter duty motors have more insulation and can therefore handle the heat at slower motor speeds.