Thank you MrAl and t_n_k for your valuable inputs. Now that I think of it, yes, if I want inductive loads in the coil to make a difference, maybe it would be best to wind it around a core. On the other hand, I want to find out how the arrangement I proposed behaves differently, and what you're proposing is that I practically build a three phase motor, and I already know how that will behave... though once I have the magnet, and assemble it with an axis and bearings and a coupled DC motor, building a three-phase winding will probably not be too much extra work... we'll have to wait and see...

Hi,

For your construction, the way it appears right now, i dont think you can use a core like a toroid. That's because the field will be outside the toroid not inside. If you look at the construction of a simple motor you'll see how they arrange the pole pieces, with turns of wire around those poles. When a magnet comes close to a pole, it energizes the pole piece and that changing field energizes the wire wrapped around it, but most important is that the pole pieces have open faces where the north or south pole comes close and that is how the pole gets temporarily magnetized.
Looking at a simple motor drawing, or perhaps taking a cheap DC motor apart, will show this better than i can explain here. The point being that the magnetic field has to be oriented in the correct manner in order for the wire to get energized by the field properly. With open wires there is no question that a moving field will do something, but with a core a little more care has to go into the orientation with the rotating field.
Maybe a simpler way of saying this is that the magnet has to be oriented directly in line with the core, in series magnetically, at least some of the time to be effective.
If this isnt clear i'll try to find some drawings.

 

Hi,

For your construction, the way it appears right now, i dont think you can use a core like a toroid. That's because the field will be outside the toroid not inside. If you look at the construction of a simple motor you'll see how they arrange the pole pieces, with turns of wire around those poles. When a magnet comes close to a pole, it energizes the pole piece and that changing field energizes the wire wrapped around it, but most important is that the pole pieces have open faces where the north or south pole comes close and that is how the pole gets temporarily magnetized.
Looking at a simple motor drawing, or perhaps taking a cheap DC motor apart, will show this better than i can explain here. The point being that the magnetic field has to be oriented in the correct manner in order for the wire to get energized by the field properly. With open wires there is no question that a moving field will do something, but with a core a little more care has to go into the orientation with the rotating field.
Maybe a simpler way of saying this is that the magnet has to be oriented directly in line with the core, in series magnetically, at least some of the time to be effective.
If this isnt clear i'll try to find some drawings.

Yet another point I hadn't considered... you're right, the whole point of a core is to function as a device for storing a magnetic field... so maybe I should build the core as a ring, and then slit it on one side using a hacksaw ... you think that would work?

 

Yet another point I hadn't considered... you're right, the whole point of a core is to function as a device for storing a magnetic field... so maybe I should build the core as a ring, and then slit it on one side using a hacksaw ... you think that would work?

Hi,

Well, if you cut a big slot in the toroid and insert the rotating magnet within the slot that would energize the core all right, but then i dont think you would be staying true to your original construction. If you build a motor for example, then it's not exactly your original idea anymore.

To stay true to your original construction i think you would have to create a bowl shaped core, maybe slotted. The wires would run in front of each section of the core (one section between two slots) and curl around the outside of the core. This way when the magnet is oriented in at a particular angle, the magnetic circuit could be pictured as through the magnet to one pole, through one wire, then through the core which brings it back to the other side of the construction which would be nearest to the other magnetic pole at that time, and so through the other side wire and to the other pole of the magnet. As the magnet moved, the poles would be nearest the next winding turn, and the same magnetic circuit would exist but with two different wire turns in its path.
This is starting to sound too unreasonable to build because the core is too complicated. Maybe you should go with a more conventional idea, or else try a higher speed to see at least SOME effect with just plain wire and no core, or possible downgrade to a construction that works basically the same way but has less turns and so would only require a simpler core construction like a "U" shape or something. Unfortunately doing this also reduces the effect. Maybe several "U" shapes each a little larger than the previous, so that the previous fits inside the next.

Maybe i should ask what you are trying to show. Are you trying to show that a construction like your original can heat wire, or generate energy, or just want an answer to that particular construction, or something else. If you want an answer to that particular construction then using a core would be very hard to do i think.

To visualize the bowl shaped core, imagine a spherical gold fish bowl made out of a good magnetic core material which is somewhat thicker than the glass on a regular gold fish bowl. The rotating magnet would be placed just inside the hole in the top of the bowl so that the two magnetic poles are always very close to the edge of the hole. There may have to be slots cut in the sides where the hole is so the field inside the core is segregated at the hole edges and also so the wires can be run inside and outside the core. It would not be easy to build this.

 

A good way to do this is with something like a disc brake. Spin a platter - like a brake disc - between two magnets oriented like the brake pads on either side. Connect the opposite poles of the magnets, the poles not facing the rotor, with magnetic iron to complete the field lines. This concentrates the field into the gap between the two magnet faces.

Oh crap, I've just described Faraday's design.

 

... so maybe I should build the core as a ring, and then slit it on one side using a hacksaw ... you think that would work?

No that would be the wrong approach. Certainly a ring core. But the core would have be constructed by stacking electrically isolated thin annular laminations to prevent eddy current drag on the rotor. A core construction typical of real machine - albeit with a non-conventional winding.

 

Faulhaber invented a motor with a core-less winding and looks surprisingly similar to this coil.
Fauhaber and Maxon still make these light-weight, cog-less and fast accelerating motors.

Sooo, maybe Mr. @cmartinez is onto something... although, in the case of the motor, the magnet is stationary and the basket spins.

http://forum.atlasrr.com/forum/topic.asp?TOPIC_ID=63598

 

Faulhaber invented a motor with a core-less winding and looks surprisingly similar to this coil.
Fauhaber and Maxon still make these light-weight, cog-less and fast accelerating motors.

Sooo, maybe Mr. @cmartinez is onto something... although, in the case of the motor, the magnet is stationary and the basket spins.

http://forum.atlasrr.com/forum/topic.asp?TOPIC_ID=63598

The commutator is the game changer. That's where the OP's concept deviates from a working machine.

 

Sooo, maybe Mr. @cmartinez is onto something...

Thanks Gopher... that's the closest thing to a compliment you've said to me... wait a minute... you're not gonna ask me for a loan, are you?

 

I mentioned my goal in previous posts, to generate a higher amount of heat at the same RPMs

But surely that is not your sole, long run interest? Sorry to be dense but I don't see the point of generating heat by spinning magnets and fancy wire arrangements, and recreating experiments done a century or more ago.

 

The commutator is the game changer. That's where the OP's concept deviates from a working machine.

Right... I'm not trying to build a motor... I'm trying to build a high-efficiency heat generator...

 

and recreating experiments done a century or more ago.

But I wasn't born and educated a century ago... so I don't know of all the experiments that have been done in this field. Surely someone else has already tried what I'm proposing, it's just that I yet haven't found out who, and what his results were.

 

Right... I'm not trying to build a motor... I'm trying to build a high-efficiency heat generator...

Are you serious? The answer is 3.413 B.T.U.s per watt hour for anything except a refrigerant cycle kind of heat pump. Light bulbs, resistors, motors, fake amateur motors...all of it.

 

Are you serious? The answer is 3.413 B.T.U.s per watt hour for anything except a refrigerant cycle kind of heat pump. Light bulbs, resistors, motors, fake amateur motors...all of it.

Yeah... I'm serious... I admit my ignorance... would you mind enlightening me and elaborate a bit?

 

This goes back to somebody with a string on a pulley, a dropping weight, and a paddle in a glass of water. The heat of all simple mechanical processes is 3.413 B.T.U.s per watt hour. This holds true for electric loads, too.

Who did the experiment to find the constant of conversion of mechanical energy to heat?
Earlier than Watt...
Senior moments!

 

This goes back to somebody with a string on a pulley, a dropping weight, and a paddle in a glass of water. The heat of all simple mechanical processes is 3.413 B.T.U.s per watt hour. This holds true for electric loads, too.

Who did the experiment to find the constant of conversion of mechanical energy to heat?
Earlier than Watt...
Senior moments!

Mr Joule.

http://en.m.wikipedia.org/wiki/James_Prescott_Joule

 

This goes back to somebody with a string on a pulley, a dropping weight, and a paddle in a glass of water. The heat of all simple mechanical processes is 3.413 B.T.U.s per watt hour. This holds true for electric loads, too.

Who did the experiment to find the constant of conversion of mechanical energy to heat?
Earlier than Watt...
Senior moments!

There you go... NOW I remember... but my question remains... would my apparatus be more efficient in this conversion than a regular electric motor loaded with a heating element?

 

No. You can't get there from here. You aren't at the lowest possible level of sophistication with your experiment, but you are at the lowest possible constant to convert work to heat.

 

Interesting to note that Wikipedia states Joule was a physicist and brewer. An important combination perhaps. How many good ideas started out in a pub?

 

No.........

Nice and dry... like a good old-fashioned martini...

WHY NOT???

 

WHY NOT???

Because you're up against a physical constant like, P=IE, and you're saying, "If I use some I and some E to run a motor to spin my magnet inside my coil, why can't I get more heat out than the power I put in? Because all you did was change the form of the power from electricity to heat. It doesn't matter how many machines you put in the path, the sum of all energy input to the system = the amount of energy the system has.

You're dangerously close to making this a Perpetual Motion thread.