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Highest Efficiency Electric Motor

Featurng Zero Hysteresis, Negative Inductive Reactance, and Minimal Eddy Currents
  [vote for,

Existing electric motors today are about 95% efficient in converting electric power to mechanical power. The four main ways they lose 5% of their power are electrical resistance, hysteresis, inductive reactance, and eddy currents. The first problem could be solved with the use of superconducting wiring inside the motors, and indeed there are a few that have been built, mostly as university-level research projects. Since they all require specialized conditions in which to operate (liquid nitrogen temperatures or even colder), they are not likely to see wide use, and so until room-temperature superconductors are developed, we will just have to live with electric-resistance losses. The next two problems, however, can also be eliminated, as will be described below. The last one, eddy currents, is likely to be significantly reduced also, but that is just a side-effect related to choice-of-materials. Finally, you might be surprised to learn that the final result of all this motor re-design may turn out to be somewhat less than thoroughly practical for wide use, but that just means the HalfBakery is the perfect place for this to be described! NOTE: The word "iron" appears frequently in this text. I am using that as a stand-in for whatever superior-magnetic-properties-alloy that you might prefer to specify.

Hysteresis and eddy currents
For an explanation of hysteresis, see the "transformers" link below. The key item specified there is a "magnetically hard" type of ferrofluid. This electic motor will employ ferrofluid, with preference for a magnetically hard type, and hence will have zero hysteresis losses. Note that (1) ferrofluid is used in place of iron electromagnet cores, (2) iron conducts electricity while ferrofluid does not, and (3) eddy currents (tiny circular flows) happen inside the iron because it IS an electric conductor. Replacement of the iron with ferrofluid therefore means that eddy currents will largely be eliminated. I doubt that they can be entirely eliminated, because typically more iron is used in an electric motor than just electromagnet cores (also known as "poles"). Also, a magnetically hard ferrofluid will include metallic (hence conductive) particles that may well experience micro-eddy currents.

Those who already know what inductive reactance is can skip several paragraphs (to "Electromagnet 3, perhaps). For those who don't, let us first examine that word "inductive". Consider these sketches:
o o
( (o)o)
Think of each small circle as being the cross-section of a wire that is passing through the face of your computer monitor. In the first sketch no electric current is flowing; in the second sketch some small amount of power is flowing through the left wire only, and as a result that wire is surrounded by an equally small magnetic field (a full circle, which cannot be sketched so easily). In the third sketch the flow of power has reached its maximum value and the associated magnetic has also reached its maximum value. Note that in order to expand, the magnetic field has to pass through the neighboring wire. One of the basic facts about Electromagnetism is that whenever a magnetic field passes through a conductive substance, some electric current is "induced" to flow in that substance. (This is exactly how eddy currents are started.) So, in the third sketch above, you can be sure that some current will be induced in the second wire, and that current will be accompanied by its own magnetic field (not portrayed).

Electromagnet 1
Now we digress to consider this sketch:
o o o o o o(o)
.o o o o o o
Think of this as a cross-section of a simple iron rod surrounded by a coil of wire. Electric current is just starting to flow into the coil from the upper-right. Pretend it is flowing INTO the screen at that point. The wire curves around the rod, so the current will flow OUT of the screen at the lower-right circle of the sketch, and again INTO the screen at that second circle from the upper right. Thus do we know that all the portions of wire in the upper part of the sketch will have current flowing through them the same way, while all the portions of wire in the lower part of the sketch will have current flowing through them in the direction opposite to that way.

Inductive Reactance
Now, consider again that third sketch in the "Induction" section above, and think about the induced current in that second wire. Which direction will it be flowing? Sadly, it always flows in the opposite direction of the current in the first wire! So, returning to the "Electromagnet 1" sketch, we see the problem of Inductive Reactance: the current about to be induced in the adjacent section of wire is not going to flow in the same direction as we want the main current to flow, in the coil of wire! Energy is wasted in overcoming the inductive reactance of electromagnet coils -- and such coils are found in just about every electric motor on the planet. This is not so bad for any motor coil that is activated and KEPT activated, with current continuously flowing the same way through it. Induction (and inductive reactance) only happens when a CHANGING-strength magnetic field passes through a conductive material, so for coils and Direct Current, there are only momentary power-wastages when the current is first turned on, and later when it is finally turned off. But almost every motor coil out there is actually energized and de-energized many times per second, and so the energy wastage associated with inductive reactance is constantly present.

Electromagnet 2
Consider this sketch:
This is a much shorter version of the electromagnet described above. It only has a single turn of wire around the iron core, and obviously would have no problem with inductive reactance. But is this a sensible idea? Yes AND No! There is a formula that is used to compute the strength of the magnetic field of a simple electromagnet (NOT including the iron core!), and three relevant elements of that equation are these:
(current flow) multiplied by (number of turns of wire)
divided by (length of electromagnet)
That "number of turns of wire per unit of length" is the reason for the "Yes" above. Both this sketch and the Electromagnet 1 sketch have the same number of turns per length, and so, if the current flowing through both is the same, then both will have the same strength of magnetic field. But that "No" above comes from the fact that this is not very much magnetism, and so in the real world, multiple layers of wire are typically coiled around a magnet core -- which is made of iron.

Electromagnet 3
In this sketch the previous one has been turned sideways and expanded:
(o)o o o o||o o o o o
The core of this electromagnet is represented by the || in the middle of the sketch, and there are five layers of wire spiralling around it. This counts as five times the "number of turns per length" as before, and so the total magnetism would be five times as before. However, now the problem of inductive reactance has returned! (With current just beginning to flow at left, note expanding magnetic field about to pass through adjacent portion of wire.) What can we do about it now? Well, think about that current flow for a moment. If we suppose that 1 ampere flows, then we have a total of "5 ampere-turns" surrounding our single unit of length of iron core. We could in theory get that much just by putting 5 amperes of current through Electromagnet 2 above, but what if the wire is so thin it is not physically capable of handling 5 amperes (and this is common)? NOTE: while a multiple of 5 is being described here, you can choose any other multiple you prefer.

Electromagnet 4
How about this:
In this cross-sectional view, the 5 turns of wire have been merged together into a single washer-shaped "turn" of wire around the iron core Obviously it can accommodate 5 amperes of current, and since we are fitting this into the same single unit of length as before, the strength of the magnetic field will be the same as Electromagnet 3. But because we only have one turn of wire, we also have zero inductive reactance! Now I doubt that I am the first person to think of such washer-shaped single-turn coils, and I am pretty sure that part of the reason they aren't implemented (at least I've never heard of this being implemented) is related to the overall capabilities of the electric power grid. If we replaced every motor that draws 1 amp of power with an equivalent motor that draws 5 amps, then the grid would be overloaded in short order! Yet there is a solution to that, too, and maybe I am the first to think of this: Just shave that washer-shaped coil down to something like paper-thickness, so that again it only can carry 1 ampere. We can still have the same magnetic field strength as before, because the associated length of iron core can also be cut to 1/5....

Magnetic Saturation 1
The reason that iron is used in electromagnets is that it can amplify an initial magnetic field. The field that surrounds a wire causes (besides eddy currents) some of the magnetic domains in the iron to align -- and those cause OTHER domains to align, and so on. The total magnetic field is more a result of all those aligned magnetic domains than it is a result of the current flowing in the wire. There is also a Law of Diminishing Returns here; if we double the current flowing in the wire, we do not double the number of aligned magnetic domains in the iron. With respect to small initial electric currents, we may see near-doubling of the iron-enhanced magnetic field, but there is simply a limited total of magnetic domains in the iron, and it gets more and more difficult to align them all, as more and more current flows in the wire. Electric-motor designers generally pick a trade-off point, where they can obtain sufficient strength of iron-enhanced magnetic field, without excessive current flow. Still, it IS possible to force all the magnetic domains in an iron core to become aligned, and this condition is known as "saturation". It is even possible to put so much current in the coil (usually this involves superconductors) that its magnetic field becomes the same as that of a saturated iron core. In this case the core can be discarded! Becuase it no longer serves to amplify the magnetic field, and in fact its hysteresis properties are a detriment.

Magnetic Saturation 2
Consider this variant of Electromagnet 4:
Here the iron core has been made thinner, along with the washer-shaped single-turn coil. The core now possesses fewer total magnetic domains, and can become saturated more easily. However, the total strength of this iron-enhanced field will probably be somewhat less than the field of Electromagnet 4. But not necessarily a lot less! Here is where another trade-off should be considered, by the Designer. That is, it is normally important to have a considerable AREA through which a magnetic field passes, between the stator and rotor of an electric motor. That tiny central point just won't cut it.

Negative Inductive Reactance
Consider this sketch:
This is an attempt to show an overhead view of a zigzagging wire. If current starts to flow into this zigzag from the upper left, then a magnetic field will start to expand away from that wire, and pass through the next wire in the zigzag. This of course induces an opposite-direction flow of current in that wire -- which just happens to be exactly the way that we WANT it to flow! All through the zigzag, the induced currents always flow in the way that the main current is going to flow. There is no "reactance" here at all -- to the contrary, we have "assistance"! While I hesitate to claim that the current that flows out the far end of the zigzag will do so "faster than the speed of light down the total length of the all the zigzagging wire", it seems to me that such a race would be a close call!

This cross-section sketch applies EITHER to an ordinary single-turn coil, or to a pair of adjacent wires in the above zigzag. The C, and C' symbols represent directions in which a magnetic field loops around two portions of a current-carrying wire (wires not portrayed). Current flows INTO the screen at one, and OUT of the screen at the other. In the case of a coil, the central = symbol represents the iron core. In the case of a zigzag, that symbol represents an iron "fin", not unlike the aluminum or copper fins that you see on automobile radiators. The length of that fin is of course nearly equal to the length of a straight section of the zigzagging wire. Note that the magnetic field loop-directions are the same (arrowing toward the right) where closest to the core/fin. This means that the two fields work together to influence the iron, to exhibit obvious magnetic poles. HOWEVER, an iron fin has a significant problem: eddy currents! This is why the fin has to be replaced with a nonconductive magnetic material, such as ferrofluid.

The Ferrofluid Problem
In an electric motor, magnetic forces cause iron to move, and (depending on design) copper wire is just carried along for the ride (some designs have totally stationary coils of wire). Because iron has great strength, we can easily attach stuff to an electic motor, and let the moving iron move that stuff. So, suppose we replace the iron with ferrofluid, to eliminate hysteresis: How do we get mechanical force OUT of this motor? Well, please refer to the Electromagnet 4 sketch, and think of it as being a highly magnified view of the Magnetic Saturation 2 sketch. That iron core is now a small box containing ferrofluid. This box can/must be mounted securely to either the shell of the motor stator, and/or to the axle of the rotor (depending on overall design; some motors use permanent magnets). Still, this is not the optimal solution, and part of the reason for posting this Idea is to seek better ways of incorporating ferrofluid into motor design. For example, we want to minimize the distance between copper coil and ferrofluid core, so the walls of the box should be as thin as possible -- or even nonexistent, taking advantage of the fact that ferrofluid is a nonconductor. But then sealing the "roof" of the box becomes a significant issue. If mounted on the rotor, it must be strong enough to resist rotational G-forces, and keep the ferrofluid locked away. If mounted on the stator, it still must be strong enough to prevent magnetic forces from trying to pull the ferrofluid through the lid. Worse, there is a dichotomy between the desired intensity of interaction between rotor and stator (the closer the better) and the thickness of the ferrofluid lid (thinner lets it be closer, but thinner is also weaker).

The Motor Stator
Start with the cylindrical metal shell which is the exterior of the average electric motor. Along the inside of this shell, apply a flattened zigzag wire as portrayed above. Let me assume that 60 straight sections of wire will fit inside the shell. Each such section is to be parallel to the motor axle (and axis of the cylinder). In the gaps between the straight sections we place our ferrofluid "fins", and seal everything thoroughly. We must make sure that no ferrofluid can leak onto or otherwise cover any of the surface of the flattened wires. That's basically all. There will be 60 long straight thin magnetically active areas along the inside of the motor housing, and the total such area will probably be sufficient for the average Motor Designer. When the zigzag is first energized, each long section of ferrofluid will exhibit a single magnetic pole (30 "North"s alternating with 30 "South"s) oriented toward the center of the motor. (The other magnetic pole is of course oriented outward toward the motor casing -- which might need to be plastic to avoid eddy currents -- but those poles have no significant effect on the motor's method of operation.) We will directly connect the zigzag wire to the usual Alternating Current power source.

The Motor Rotor
This could be a kind of mirror image of the stator description, with standard "slip rings" being used to let power energize the zigzagging wire. But due to a likely problem which will probably be discussed in the annotations, I will at this time recommend the mounting of 60 finlike permanent magnets, all parallel to the axis of the rotor. As previously indicated, we want a very close fit between the rotor and the stator. In consequence, with the power off, each permanent magnet on the rotor will be strongly attracting a fin of ferrofluid on the stator.

Turn it on!
In the USA, ordinary electric power is supplied at 60Hz (cycles per second). Under the influence of electic power coursing through the zigzag stator wire, the ferrofluid fins will begin to either attract or repel the rotor magnets. Repulsion will set the rotor into motion, because a rotor magnet that is repelled by one ferrofluid fin will be attracted to either of its neighboring fins. (This could pose a problem in ensuring the motor always rotates the same direction. I am not Motor Designer enough to know the standard solution, but suspect that in this design, using only 58 rotor magnets, or 62 stator zigzags, will do the trick.) As is natural for electromagnets powered by ordinary alternating current, the center-pointing polarity of each ferrofluid fin will change 60 times per second (or is that 120, due to being North for half-a cycle and being South for the other half-cycle?) So, if each 1/60 of a second the motor rotor is caused to re-orient its permanent magnets to the next ferrofluid fin, 1/60 of the way around the stator, then the net effect is that this particular motor, as described, will do one whole rotation per second. That's 60RPM, rather slow.

Just Crank Up the Frequency!
Please remember that the whole point of this motor is that it should have practically zero energy losses associated with frequency-driven hysteresis or induction. This means it can handily accommodate higher-frequency alternating current. 600Hz conveniently yields 600RPM; 6000Hz yields 6000RPM, and so on. Just because such frequencies are not widely available, that doesn't matter so much, here at the HalfBakery.

Vernon, Jun 15 2004

Hysteresis described here, in Transformers http://www.halfbake...ower_20Transformers
As mentioned in the main text. [Vernon, Oct 04 2004]

Power-creating motor http://www.japan.com/technology/index.php
A motor that generates more power than it consumes (possibly not BS) [5th Earth, Oct 04 2004, last modified Oct 21 2004]

Ampere-Turns per unit of Length http://www.tpub.com.../css/h1011v1_58.htm
For [neelandan]. [Vernon, Oct 04 2004, last modified Oct 21 2004]

Here's a "free energy" outfit. http://www.steorn.net/orbo/papers/
Supposedly they are confident that an outside panel of experts will agree with their claims. [Vernon, Oct 18 2006, last modified Dec 09 2013]


       [half], magnetically active materials tend to trap external magnetic fields. That is, place a sheet of paperboard over a bar magnet, and a compass above the paper will still register the field. Replace the paperboard with equally thick sheet steel, and the compass will detect almost none of the magnetic field.
Vernon, Jun 15 2004

       I assumed this was Vernon from the title, but I wasn’t sure, so I started scrolling down using the mouse wheel, and down, and down, and there was no end to it, and I was about to give up, and finally there it was. Vernon. So I was right!
ldischler, Jun 15 2004

       Half, no extra shielding is needed. The shielding effect that I was referring to is provided by the fins that lie in-between the zigs and zags (but maybe you didn't read far enough to encounter the fins).   

       Next, suppose we look down upon a section of energized zigzagging wire, as portrayed below, and we see (top) that a North field is coming out between an adjacent pair (1 and 2).
You are asking about the field generated by wire (2) affecting wire (4), but you aren't noticing the repulsion of that other North zone which lies between!. Admittedly, when first being energized, that second zone takes a moment to spring into existence, but then, there is ALSO the fact that if current in (2) induces assisting current in (3), then THAT current works to assist the current in (4). Surely this will effectively counter the effect of (2) upon (4). OK?
Vernon, Jun 15 2004

       Hi [Vernon], have you ever thought about indexing?
Well, I managed to read through your idea, but have difficulty in going back to review certain parts.
But from what I remember, there were a couple of major points that I would like to raise:
1. Induction energy loss. I have never associated induction as energy loss: only energy storage (stored in the magnetic field). Induction is usually used to restrict the operating current of motors, fluorecent tubes and so on. The total induction of an ac squirrel cage motor depends on its speed of rotation. At stall, the inductance is lower and current is higher.
2. Thin washer conductors: in this case you intend to use resistance to control the current. Resistance = heating = energy loss. i don't think this is quite the correct concept. Maybe you ought to review what I think are called PCB pancake motors. Note: for high efficiency, use larger cross section conductors, and control current using voltage!
3. I cannot easily visualise the magnetic circuit. Maybe I'll leave that for later.
4. What is the advantage of Ferrofluid over Ferrite?
5. Your basic topography seems to be that of a stepper motor.
6. Anyway, a quality post, so +, even if I have some concerns.
7. For a severe bruising, try submitting to Google groups sci.physics.electromag.
Ling, Jun 15 2004

       When efficiency (in almost anything) reaches 90% or so, each % is much harder and more expensive to acheive than the last percent gain. Usually 95% efficiency is quite acceptable. If an extra 2-3% can be gained cheaply, we'll take it. If it increases the motor cost by more than a few cents, it probably isn't worth it. An exception would be huge motors of 100 HP and more.
bobad, Jun 15 2004

       Thanks, [Ling]. (1) Yes, in electronic circuits inductors (coils) are temporary energy storage devices. But whether or not induction is good or bad in electric motors depends on the motor. As you say, squirrel-cage motors are designed to work with induction. But consider more carefully what you wrote about using inductors to restrict an operating current: If the wire in a particular coil can carry 2 amps, and you want it to carry 2 amps, then ignoring induction and examining only the resistance of the wire, one can compute a voltage that will push 2 amps through that wire. Now remember that Watts=Volts * Amps, and add the fact that induction in the coil restricts the current. If you still want 2 amps to flow, then you have to boost the voltage to overcome that inductance -- which means that the presence of inductive reactance in that coil causes it to consume more watts than if induction wasn't present. That qualifies as inefficiency in my book.
(2) I have no objection to controlling voltage, in order to push the desired amount of current through an induction-less motor. The purpose of describing washer conductors was merely to show that a desired amount of magnetism need not depend on lots of windings.
Here is an attempt to show polarities around a cross-section of a zigzagging wire (assuming Direct Current):
` N ` S ` N
-- | -- | -- | --
` S ` N ` S
The middle layer is passing through the screen; the (hoizontal) flat conductors are separated by exaggerated (vertical) fins, the edges of which are the magnetic poles. (ignore the accent marks, which are only there to help space out the other symbols)
(4) Being a solid, the magnetic domains in ferrite are not necessarily any easier to flip around than the magnetic domains in any other solid-magnetic-core material. Being liquid, a ferrofluid easily allows domains to flip. For more info, see the "transformers" link.
(5) It did occur to me that single pulses could cause the described motor to step. But I do think that continuous AC will cause it to run smoothly, mostly because of Conservation of Angular Momentum of the rotor. On the other hand, it is possible that using permanent magnets will always be associated with some tendency to step, because they are constantly attracted to the ferrofluid. This is where using electric-powered magnetism on the rotor could be superior.
(6) Thanks again!
(7) I have encountered bruisers in sci.physics before. Thanks for the reminder; I didn't happen to think about seeking an appropriate special-interest group there.

       [bobad], yes, I know. I'd like to think that some of those last few percentage points can be gained by appropriately clever designs, as suggested herein. I'd be interested in seeing what professional Motor Designers could come up with, starting with these notions.
Vernon, Jun 16 2004

       Didn't read it.   

       I have taken apart several types of motors, just to see how they work. And my course on engineering included two papers on Electrical Machines.   

       Changing the geometry of the pole pieces is not going to do anything to the inductance or efficiency. These things are inter-related. Motors of wildly differing construction can have similiar electrical behaviour and efficiency.   

       The blahblah on the left is just wishful thinking from an addled brain that grew up on too much science fiction too early.
neelandan, Jun 16 2004

       Christ, Vernon! Come up with something simple, like a new theory of space and time or something.   

       On another note, have linked to an article about a japanese guy that has apparently made a motor with negative power usage. Read the whole thing before you laugh it off, with a bit of thinking you can see where the excess power is coming from.
5th Earth, Jun 16 2004

       3,092 words (excluding additional annotations). Is there any way to paraphrase this idea?
Klaatu, Jun 16 2004

       [Vernon], Equally, when you remove the driving voltage from an inductor, the current continues... Induction does not consume power, it stores it. Yes, more voltage is required to get current, *initially*.
[5th Earth], most of these over unity delusions arise because the experimenter does not know about power factor (that is when the current is out of phase with the voltage). You cannot simply multiply V.I to get power.
More fool the investor.
Ling, Jun 16 2004

       [neelandan], while the described motor may seem excessively simple, I will be quite surprised if you can point out any really significant factual errors in the background explanations. (Go ahead; I dare you!)   

       [5th_Earth], for my speculations regarding space and time, see "T.O.E. Essays" in the OTHER:Gravity section of the HalfBakery. :)   

       [Ling], yes, when you remove the driving voltage current does tend to keep flowing, because of the inductance. I do know that this "continuance" when removing power is just exactly the opposite of the "resistance" to the initial flow when first sending power through an inductor. Still, in an AC system, when you are wanting the voltage to reverse the current flow (and magnetic polarities), that is NOT a plus.   

       --And, I agree with what you said about "overunity" motors. The simple proof is to hook that motor to a generator, and see if the power from the generator is sufficient to keep running the motor. I will believe in overunity motors only after I see such a connected system working.
Vernon, Jun 16 2004

       And once it's working, please disconnect it before it turns itself into a bomb that destroys the universe.
RayfordSteele, Jun 16 2004

       Way too much time on your hands.
DesertFox, Jun 16 2004

       //(Go ahead; I dare you!)//   

       Vernon has thrown his prolific keyboard into the ring. That patter of feet you hear is the sound of neil and dan both retreating in panic.   

       I'm sorry, Vernon, I do not intend to read the idea. I've prepared rebuttals to your ideas in the past. I posted one or two (IKECE, electrolysis) but threw the one on 12864 away as I realised that it (what I wrote) was all a load of crap. A refutal of some mis-applied scientific principle has some educational value. A rebuttal of someone's "not even wrong" box of magic tricks is a waste of time. Of me to write - once. Of others to read - many times. Sometimes, somethings make me realise that life is too short.   

       I must thank you, Vernon, for that.
neelandan, Jun 18 2004

       Oh, and that power creating motor linked by 5th earth. Probably a measurement error. The motor is drawing current in pulses of low duty cycle. Most low-quality meters will have trouble integrating that current and will report a vastly lower value.   

       If somebody makes measurements with accurate meters the real efficiency will be revealed as being less than unity and the inventor will accuse them of using "doctored" instruments.
neelandan, Jun 18 2004

       <neelandan>Most low-quality meters will have trouble integrating that current and will report a vastly lower value.</neelandan>   

       Does that include domestic electricity consumption meters??? ;-)   

       Might be a cost saving motor, but not necessarily an energy-saving one. If so, I will hook up one to draw power to generate in my local loop...or even sell back to the grid...bwahhahahah!
timbeau, Jun 18 2004

       timbeau: Most utilities restrict the power factor of the load you can connect legally.   

       A very spiky current waveform will have low power factor, and probably be illegal.
neelandan, Jun 18 2004

       [neelandan], if you are going to make accusations like "The blahblah on the left is just wishful thinking from an addled brain that grew up on too much science fiction too early.", then you had better have the competence to be able back that up with evidence. Thus the dare, since (1) I am confident I have the facts correct, there on the left, and (2) I want to determine the accuracy of my low opinion of your own abilities.
Vernon, Jun 18 2004

       [Vernon] Is your real name Tom Bearden?
ConsulFlaminicus, Jun 18 2004

       [ConsulFlaminicus], no. I don't know what Tom Bearden's game is. If he really has a gadget that produces significant electric power from the vacuum self-energy, well, it cannot be all that tough to convince everyone.   

       See, most US States have rules saying that if some person has, for example, windmills and solar cells, and so on, and generates more electric power than he needs from the Power Grid, then the Power Company MUST allow that person to sell power to the Grid. Even if only a few hundred watts.   

       So, all Tom Bearden has to do is hook his device to the Grid, and start selling power. After he makes enough money, he can build a bigger device and sell more power. This can snowball until (A) he's supplying the entire Grid with power, and (B) everyone is convinced that his gadget works. Heh, few pleasures are greater than getting rich while saying, "I told you so!"
Vernon, Jun 18 2004

       Yeah, I really did intend on at least trying to understand what all's going on to the left here, in spite even of talk about ferrofluids and winding styles that make no sense. But the minute I saw a plastic motor housing suggested, I knew I was looking nose-first into a steaming crock of BS. I dare you to find any heavy machinery manufacturer that is gonna trust a motor with anything but a forged or cast housing.   

       I think I've figured out Vernon's style. His boggishly crafted essays will confuse even an expert while muddling the less informed into thinking "hey, this guy must be onto something REAL advanced..."
otmShank, Jun 19 2004

       hey, this guy must be onto something REAL advanced..   

       and [5th Earth], I won't be able to sleep until you or anyone explains why that link is bogus.
Cheekio, Jun 20 2004

       [otmShank], some plastics, notably polycarbonates (Lexan) are about as hard as some metals (probably aluminum). Also note that a plastic housing could be sufficiently THICK to have as much strength as, say, iron.
Vernon, Jun 20 2004

       I'm a designer. What I describe, I have to make or have it all rammed down my throat.   

       I suggest you build the motor you have described here, Vernon, then you can verify the accuracy of whatever thoughts you have.   

       I've been wrong so many times that my opinion of my own abilities is at an all-time low, right now.
neelandan, Jun 21 2004

       [neelandan], thank you for your honesty. If you had read the main text, you would have seen (in "The Ferrofluid Problem") that part of the reason for posting this Idea was to seek better ways of incorporating ferrofluid into motor design, than the method suggested here. I don't really want to build one until that issue is well-resolved. Until then, we cannot consider it to be baked sufficiently.
Vernon, Jun 21 2004

Were I to install a motor which had net output of, say 1kWh for every 100 hours it's online -- is my electric meter registering only power input? That is to say, do I pay for using 100kWh equivalents, 99kWh equivalents, or do I receive a rebate for 1kWh equivalent fed into the grid?

       *If my answer is in the text, I'm sorry. Were this about protein binding or similar I might be inclined to read a little deeper.
dpsyplc, Jun 21 2004

       FOLKS, before reading this, please keep in mind that the main Idea here concerns ways of more closely reaching 100% efficiency. Others, not I, are making claims of passing 100%. So far as I know at this time, that cannot be done, no matter what they claim.   

       [dpsyplc], let me try to answer what I THINK you are asking:
If I had a motor with a net output of 1kWh for every 100 hours it's online, can I assume that this is an "overunity" motor we are talking about here? That is, 1kWh is something over 1 horsepower, working for 1 hour. If it took 100 hours to get that much work out of the motor, I'd replace it with something more efficient! But if we are discussing some quantity of energy over-and-above 100% of the supplied power, then let us start by calling that "supplied power" X. So, all this means is that the force coming out at the axle can be applied to something heftier than usual for a mere 100% efficient motor, also being supplied with amount X of power. Either way, you would be drawing the same amount of power (and your electic bill would be the same); you could just do more with the overunity motor.

       Now, IF that motor is hooked to a generator, and IF the output of the generator was still more than the amount X supplied to the motor, then this could be due to either having an overunity motor or an overunity generator. (Note that if either is ORDINARY, at say 90-95% efficiency, then the degree of overunity of the other must make up the difference, before the net output is worth selling.)
Vernon, Jun 21 2004

       Once again, a [vernon] idea that's too long to read. I got about as far as the zig-zag mesh of wires replacing a coil. Any current-carrying wire has a magnetic field. Coiling the wire just concentrates this field. If you make the wires zig-zag back and forth, you'll wind up with the same magnetic field as a single wire (if the leads exit on opposite sides) or none at all (if the leads exit on the same side). The opposite fields generated by each pair of wires in the mesh will cancel each other out.   

       I could probably find more flaws in the logic, but I don't feel like reading all of it.   

       Oh, another thing just crossed my mind. A feature used by RC racers is applicable here. A motor with few thick windings will be capable of higher speeds, but will have less low-end torque. A motor with many thin windings will have lots of low-end torque, but won't be able to spin as fast. Your single-coil winding is the extreme of the first type.
Freefall, Jun 21 2004

       Higher efficiency Electrical Motor:   

       Take a stock Induction motor. Dismantle. Take off the cooling fan. Cut off those protuberances on the rotor, intended to draw air for cooling. File rotor smooth and finish with sandpaper. Reassemble.   

       This motor will be at least a few percent more efficient than a stock unmodified one. (So buy two, and keep one aside for comparison)   

       Vernon should buy two stock motors, make his modifications to one and demonstrate superior efficiency. // (Go ahead; I dare you!)//
neelandan, Jun 22 2004

       [Freefall], there will be magnetic fields in-between each pair of zigzagging wires. While it is true that you can closely align two wires that carry opposite currents and FROM A DISTANCE have no overall magnetic field, up-close-and-personal there will indeed be useful fields. The paragraph labeled "Electromagnetism" explains this, but since you jumped to the wrong conclusion, regarding how zigzagging wires can be used, your logic is much more faulty than mine.   

       Regarding the motors with different numbers of windings, part of reason for the differences is related to the voltage that the designer wants the motor to use. Fewer windings means less resistance in the wires, and less induction, so less voltage is needed. And since power (watts) = Volts * Amps, this normally also leads to a low-power (and low torque) motor. However, with no load, even a low-torque motor can run at high speed.   

       I expect the motor I described here to use relatively low voltage (it doesn't have a whole lot of wire in it), but have moderately high torque (relative to similar-voltage ordinary motors) and a frequency-dependent RPM.   

       [neelandan], you make it sound so easy. It isn't. Didn't you read my last reply to you? Not to mention that the described motor is NOT an induction motor (it does not deliberately induce currents in the rotor so they can create magnetic fields that interact with the stator-coil fields).
Vernon, Jun 22 2004

       Lemme see. I'm going to install a big and expensive generator at my place, that will generate enough power for my house plus extra power to feed into the grid. I'll need a jolt from my utility company to set it spinning, but the solar panel on the roof juices the generator at points of highest impedance so it continues spinning indefinitely while consuming a trickle of utility company current. This is possible because racemized ceramic/metal wires and the closely-held design of the generator's electromagnetic scatterband manage to confine impedance to a razor thin grid within my generator's stator? Sounds okay.
dpsyplc, Jun 22 2004

       [dpsyplc], that sounds like gobbledygook. Please refrain from implying any association of the motor I described in the main text with some kind of "overunity" principle or device. Thanks!
Vernon, Jun 22 2004

       //the described motor is NOT an induction motor// OK. So what is it? I gritted my teeth and read it, finally. gobbledygook.   

       //But because we only have one turn of wire, we also have zero inductive reactance!// Wrong. Even a straight length of wire possesses inductive reactance. If there is a magnetic field, there is inductance.   

       //We can still have the same magnetic field strength as before, because the associated length of iron core can also be cut to 1/5 // Wrong. Magnetic field strength is proportional to the ampere-turns. The length is not a factor.   

       But, finally , the clincher://I am not Motor Designer enough to know the standard solution//   

       This is something like the butcher presuming to teach a neurosurgeon some tricks, so that he can "make his patients get well sooner".   

       I rest my case.
neelandan, Jun 23 2004

       [neelandan], I hope you had fun. The motor as described simply creates alternating magnetic fields in the stator, that attract/repel permanent magnetic fields in the rotor. Nothing out of the ordinary (for small motors, that is).   

       I confess I never heard before, about a straight segment of wire inducing current in itself. Seems like the only way that could be, is to dive into the wire and watch the electrons initially being pushed by a just-applied voltage. Each electron is then surrounded by an expanding magnetic field that tries to make its neigbors go the wrong way, is that it? How significant is this effect, compared to the USUAL description of inductance, which involves neighboring wire segments? (Remember I dared you to find SIGNIFICANT errors....)   

       //We can still have the same magnetic field strength as before...// YOU are wrong; the equation DOES involve ampere-turns per unit of length! I just added a nice simple basic electrical theory link to back that up. (I should mention, however, that the reason I specified cutting the iron core to 1/5, in that context, was because the coil described at that point had also been cut to 1/5, and there is no reason to carry the excess iron around.)   

       The parts I knew well, I did well with them. For example, I see you are not supporting the claim made by [Freefall], so I can assume you understood what I was describing there. And I was up-front about what I didn't know. Just because I don't know the standard trick for ensuring a motor rotates the same direction whenever it is turned on, that does not mean the motor that I described cannot work with the efficiency I was aiming for. (I notice you didn't say anything about that, either.)
Vernon, Jun 23 2004

       You'd like it better if we all ganged up, huh?
neelandan, Jun 24 2004

       Congratulations on reaching the end of the original post :)
Ling, Jun 24 2004

       [neelandan], regarding "ganged up", just look at the fishbones here, heh heh (hmmm...those apparently got lost in the Great Hard Drive Crash; I expect they will eventully return as the Idea is revisited). But the really funny thing is, this Idea describes a quite workable device which should be quite as efficient as indicated, and yet because it only runs at 60RPM (maybe 120), it probably has few practical applications. Thus, perfect for the HalfBakery! I would have expected some buns for that reason if none other. But I suppose there is too much disbelief. You could be right; if I toss out an army of ideas, then maybe you need to gang up, to handle them!
Vernon, Jun 24 2004

       ...not that I really want to wage in here, you sparkamatricians all talk what sounds like french to a knuckle-dragging mecho like me.   

       -but I have two points:   

       1) //the standard trick for ensuring a motor rotates the same direction whenever it is turned on,// I don't think it's as simple as that, there must be different architecture for different motors. Case in point, it is not all that uncommon for pump motors without softstart or V-VF on them to start up running the wrong way. A conveyor with VVF will never start running backwards. I know this because we have to pull down pumps that tried to run arse-about, but conveyor drive gears are rediculously forward-biased, and I've never seen any wear on the reverse side of teeth, or heard of any failures like that.   

       2)A 60rpm motor, as you have stated probably doesn't have too many applications. Also, there are efficiency advantages to spinning a motor fast, which have to do with being able to reduce shaft diameter/mass. As speed goes up, for a given power output, torque goes down, and hence you can shave off shaft mass. just thought I'd mention it.
Custardguts, Feb 08 2007

       [Custardguts], most AC "induction" motors have a small "wiring junction" area, where the outside power wires are brought in and connected to the motor. In every case that I know of (induction motors only), there is a pair of wires in that junction that can be swapped, to determine the direction of rotation. And once set, the motor always rotates that direction. Your conveyor is probably powered by this kind of motor. Meanwhile, other electric motors, often those that have both a rotor coil and a stator coil, especially those in simple "here's how to build an electric motor" projects, can spin in either direction when power is first applied to them. The VVF thing you mentioned is probably for this type of motor.
Vernon, Feb 08 2007

       Sorry Vernon, VVF meand Voltage Variable Frequency. It's a bit like putting a big PWM controller on large industrial motors: gives excellent speed control but costs shitloads.
Custardguts, Feb 08 2007

       Bun for the explanation of induction, with diagrams. Thanks.
bungston, Dec 09 2013

       The problem here is experimentation and prototyping. Ultimately the universe says yea or nay.
wjt, Dec 09 2013


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