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# Generator

08/02/2017 12:46 AM

So what I am proposing here is a generator. I have taken a mild steel core or iron core , 65 cm in length . Now at variable interval , I cut three cross section . First at 7 inch from the north pole having a air gap of 2 inches . Second at 17.75 inches inch from the north pole having a air gap of 2 inches , third at 22.97 inches from the north pole having a air gap of 2 inch .

Now I insert coils into the air gaps , that's three coil for 3 air gaps. Now the first air gap I am producing a DC emf . This produced , it will all be goes to the wire that is turned around the 65 cm iron core or mild steel. I have reversed the wire loop in every air gap so every air gap has north and south pole at a distance of 2 inches .I am using only one wire to cover the entire core like this. The next two coils are generating output . The first coil is rotating at 30 rev/sec - 35 rev/sec. This value is fixed . The others two coils are rotating at revolution that does not matter much related to this forum .

This is my system . I need help on following things

1) what is the maximum magnetic field that I can generate in the air gap.

2) what is the maximum emf I can generate in first air gap.

3) what is the resistance of the wire i should used . ( By the way I have thought of using copper wire as it's reactance is 1.63 * 10 ^ -8 .)

4 ) based on the above things heat loss and how can I minimise it .

5) power equation given by V*I

6) what should be the number of coils and current and flux in the first air gap . ( E= PBAFN) where P number of poles , B magnetic field , A area F frequency and N number of coils.

7) what value should I take of voltage and current and resistance in the circuit that will cover the core with wires?

You can take your own value of current or magnetic field as you see best. But can not change the system . Number of coil and all you can take , but can not change the distance and all.

In short , making the system viable and working , deriving the parameters . I need help on this

Pathfinder Tags: Generator coils emf
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#1

### Re: Generator

08/02/2017 3:06 AM

A1) It is highly unlikely that any other subscriber has built anything similar, so try it, and tell the forum the outcome.

A2) It is highly unlikely that any other subscriber has built anything similar, so try it, and tell the forum the outcome.

A3) As low as practicable given the space constraints indicated and the number of turns needed.

A4) Don't connect any load to it.

A5) The Maximum Power Transfer Theorem states it.

A6) The equation answers the question.

A7) The question makes no sense here.

<...take your own value of current or magnetic field as you see best. But can not change the system . Number of coil and all you can take , but can not change the distance and all...> Invitation declined; personal projects are taking priority.

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#2

### Re: Generator

08/02/2017 3:15 AM

I did try . After trying I am writing this forum . But I want a second opinion. I just want to know what will be the best numerical values for such a system for a given parameters . I am unsure of my numerical values because there can be a point or two which I may have missed which can bring out error . That's why I am asking here .

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#3

### Re: Generator

08/02/2017 3:16 AM

See A1 in #1⇑. <...did try...> Then describe the outcome to the forum!

One of the options is to write to Admin and request a Blog-spot.

• "A picture is worth a thousand words" - Anonymous Poster #0
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#4

### Re: Generator

08/02/2017 3:24 AM

Why the last one holds no sense ? Can not I use a transformer to increase voltage and reduce current and there by reduce the heat loss ? I think that's valid .

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#5

### Re: Generator

08/02/2017 3:24 AM

Nonsense.

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#6

### Re: Generator

08/02/2017 3:26 AM

But explain why ?

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#7

### Re: Generator

08/02/2017 3:29 AM

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#10

### Re: Generator

08/02/2017 4:51 AM

All right here comes my calculations .

I wanted to produce a 1.2 T magnetic field . So I put the value of 1.2 T and I have use hit and trial method and thought of using 3 A current . I then calculate the number of turns per unit length . Which came out to be 80 if I am using mild steel whose permeability is 5 * 10^-3 . ( Equation used here is B= mu * I*N/l where the respective symbols holds the common value of I being current in amperes , N/l being number of turns per unit length . And B to be magnetic field in Tesla .

Then I calculated the emf by the formula mentioned in the forum . That came out to be 259.2 V . ( E= 2( poles ) * 1.2 (B) *0.03(A) 0.8(coswt) *30(F) *150 (N) )

The area of the coil I have taken above , don't get confused with 2 inch .

Then I calculate the resistance using R= rho*length/area of the cross section of wire.

I am using copper wire so it's reactance is 1.6*10^+^-8 . I multiply it by 5000 meters ( just a assumed value, not real if I can get it right in this value then the real one would get it automatically ) and cross section of wire 0.785 as I have assumed radius to be 50cm. The resistance came out to be in 10^-5 . ( I forgot a little )

By judging this value I knew that I am wrong somewhere , hence I posted the problem here . I am just skeptic about the values .

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#11

### Re: Generator

08/02/2017 5:07 AM

So build it like that, and test the calculations. Let the forum know the outcome and whether the calculations reflect reality.

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#24

### Re: Generator

08/02/2017 1:23 PM

You need to make sure your (metric) units are consistent throughout the calculations. Use MKS units, and there will be no order of magnitude conversion errors.

Copper 1.68 x 10-8 Ohm-m. That means your wire diameter should be given in meters and not mm, as it appears to have been. Try again with consistent units.

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#25

### Re: Generator

08/02/2017 1:29 PM

Thank you for your comment . And yes I will recheck the conversion . I have used in MKS system .

So far only your comment has helped. Thank you .

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#27

### Re: Generator

08/02/2017 1:32 PM

That is the same place I usually find my errors: right where I laid them.

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#32

### Re: Generator

08/02/2017 6:03 PM

If you refer to "Solenoid Best Adjustment Part 2" reply post #1 and the B-H curve in it, you will see that for 1.2 T [Weber/m2] in mild steel you need 1000 A-t/m. Since B = mu*H, then mu = B/H = 1.2/1000 = 1.2 x 10-3 . So your assumption of 5. 10-3 for permeability is much in error.

You have an air gap of 150mm total - as I wrote, every mm takes 800 A-t per Tesla. Thus you need about 100000 A-t or 33000 turns @3 amp. This is not practical, let alone efficient.

If you look carefully at the B-H graph, you will see that B/H is far from constant. It is low at low and high H and best at the "high slope" region between. Designers look at B-H curves rather than permeability figures (which might be absolute, B/H, or incremental, ΔB/ΔH, or at not-given flux density - when they are not properly stated).

The irons like stalloy, in B-H graph, are made in thin sheets for motors & transformers and have better permeability than mild steel - only 300 A-t/m for 1.2 Tesla.

Efficient motors have iron rotors with conductors buried in slots (or high permeability permanent magnet rotors) , to minimise the air gap - which is the big eater of amp-turns or flux density.

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#38

### Re: Generator

08/03/2017 1:49 AM

Thanks

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#8

### Re: Generator

08/02/2017 3:36 AM

I thought people will be as curious as I was about the project .

Off Topic (Score 4)
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#9

### Re: Generator

08/02/2017 3:40 AM

Then write a blog about it, as suggested in #3⇑, as progress is made with it.

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#12

### Re: Generator

08/02/2017 11:00 AM

I still don't understand what you are trying to do...What are you trying to do? Yes I get that it's a generator, but what is the purpose, are you trying to build a more efficient model, a certain shape to fit in a specific place....what?

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#13

### Re: Generator

08/02/2017 11:15 AM

I am trying to build a more efficient generator. I want to use it automobile industry

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#14

### Re: Generator

08/02/2017 11:33 AM

You do realize that there is a theoretical limit....? In the automobile industry how? A lot of alternator/generators are already 98-99% efficient....

http://www.mpoweruk.com/energy_efficiency.htm

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#20

### Re: Generator

08/02/2017 12:32 PM

Using it in electric cars by removing the battery . Duh

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#31

### Re: Generator

08/02/2017 4:15 PM

So what spins this generator of yours to produce the power to run the electric motor that drives the vehicle?

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#33

### Re: Generator

08/02/2017 11:05 PM

You asked that one before I could...NO battery????

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#34

### Re: Generator

08/02/2017 11:51 PM

I'm willing to speculate his plan is to use his "high efficiency generator" to power the motor that spins the generator and the excess power is used to move the vehicle.

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#37

### Re: Generator

08/03/2017 1:23 AM

See post number 36

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#15

### Re: Generator

08/02/2017 11:33 AM

So... Your plan is to redesign a product that has been in use and improved upon for over 100 years by some of the brightest minds mankind has ever known, such as Nikola Tesla, Geoge Steinmetz and countless others over that century, without any previous knowledge of the basic physics involved. And you are embarking on this by asking for free help in an anonymous Internet forum, for an industry that basically could not care less about the efficiency of something that is just an accessory

I wish you luck, you are going to need a LOT of it...

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#16

### Re: Generator

08/02/2017 11:41 AM

Cr4... where pipedreams come to die....

RIP

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#23

### Re: Generator

08/02/2017 12:46 PM

I got a better one CR4 , where you discuss something new other than sarcastic comments .

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#19

### Re: Generator

08/02/2017 12:31 PM

Yes and not luck . Just lots of hard work and persistence .

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#17

### Re: Generator

08/02/2017 11:57 AM

If you wish to accomplish new things you must stand on the shoulders of those who went before you and reach up from there using their work as your new foundation. Not stand at their feet and blindly reach out from there.

Until you have a true solid understanding of tall the the intricate details of every part of something that is already in use you cannot create something that is better than what is already here.

If you wish to make something more efficient you have to understand what is already in use and to what its efficiency limits and why are before you can improve on them which as others have said there are generators and alternators in existence that are pushing the upper limits of efficiency for what is cost effective to manufacture.

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#22

### Re: Generator

08/02/2017 12:40 PM

I believing in questioning things , and not just the saying of people . If they have said something I want to know why . I refuse to accept it only on the basis of because they said it.

And don't connect it with here by saying that we are also just saying the values of the numbers then how can you trust us . That's a lame question .

And instead of helping , good work in discouraging others to try something new even if it fails .

The one who never fails , have not try something new . - Einstien

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#18

### Re: Generator

08/02/2017 12:01 PM

Maybe Solenoid Best Adjustment followed by, Solenoid Best Adjustment Part 2 dulled the interest of members for your projects?

Also mixing units of measure is always a recipe for disaster.

What does this statement really mean, is "65 cm in length" 65 "centimeters", "65 inch length." Or "65 cm in length?" That is a rookie mistake, and one that would indicate either sloppy work or no appreciation of engineering!

All your other lengths are metric.

Finally no automotive manufacturer will look at an alternator that is 25 inches in length.

This is homework, right?

Don't make a better wheel (alternator), they're not worth the expense of development, tooling and parts stocking plus assembly that resembles nothing being made today.

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#21

### Re: Generator

08/02/2017 12:35 PM

It is 65 cm , 26 inches . This is not a rookie mistake .

And do I even care about the existing automater. I will build my own automation company.

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#29

### Re: Generator

08/02/2017 2:24 PM

"I will build my own automation company."

Arrogance won't take you very far.

And, yes, mixing units IS a rookie mistake!

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#26

### Re: Generator

08/02/2017 1:30 PM

The easiest way to analyze a magnetic circuit is to consider the analogy between electric circuits and magnetic circuits. An electric circuit may have a battery and several resistors in series. The sum of the voltage drops across the resistors is equal to the battery voltage. In reality, there is a small voltage drop in the wire, but it is negligible.

In a magnetic circuit, there is the magnetizing driver (ampere-turns) and resistive air gaps, where the magnetic drops occur. The magnetic drop in the iron, like voltage drop in wires, can usually be neglected. The flux will be limited by the air gaps. The magnetic drop for each air gap would be proportional to the width.

Bottom line, B = μ0NI/L, where μ0 is the permeability of free space, N is number of turns, I is the current, L is total length of air gaps (6 inches).

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#28

### Re: Generator

08/02/2017 1:46 PM

Nice idea . Thank you very much . I did not think it to take all the air gaps at one go . And thanks about the voltage drop explanation . It was nice.

Thanks a lot Rixter.

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#30

### Re: Generator

08/02/2017 2:37 PM

It sounds like you are trying to build a motor/generator that will run on the energy recovered from the motion of the vehicle, if so then you should Google on "regenerative braking".

If you expect such a system to be self-powered (without an internal source of power such as a battery) then you should search on "perpetual motion generators".

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#35

### Re: Generator

08/03/2017 12:25 AM

First, it's commendable that you want to create something, presumably better than anything currently existing. BUT, unless you have some new concept that no one has thought of before, you have virtually zero chance of succeeding.

"I cut three cross section . First at 7 inch from the north pole having a air gap of 2 inches . Second at 17.75 inches inch from the north pole having a air gap of 2 inches , third at 22.97 inches"

Is there some magic formula that led you to choose those particular values? An air gap of 2 inches!!! 0.02 inches is too large for an efficient device. Now if you can economically manufacture everything so the air gap is reduced to 0.002" without rubbing, then you might have something.

One more time: until you can submit a drawing or photo, no one can really know what you are proposing, so no one can really help you.

Every electromagnetic generator depends either on a changing magnetic field passing through the coil(s), or on moving the coil(s) through a magnetic field. Either of these motions requires a source of energy from the outside. What is your source of energy?

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#36

### Re: Generator

08/03/2017 1:22 AM

Yes it is a new concept .I am not telling the whole thing because I am afraid the idea would get stolen.

And about the picture , its not uploading , I don't know what's the problem is .

Yes , the distance are fixed , not magical formula but more of a size depends constraint .

Thank you very much for your comment .

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#41

### Re: Generator

08/03/2017 10:39 AM

Sounds like over unity to me.

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#42

### Re: Generator

08/03/2017 11:39 AM

Well we haven't had one of those believers come through here in a while 'to show us how we are all wrong' so I guess it's about time.

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#39

### Re: Generator

08/03/2017 6:31 AM

I am a bit late but here is something none has said yet.

Raj, you are making many FORBIDDEN building technics that will make your system useless.

1. You cannot magnetise with DC currents and obtain otput power. Output voltage requires flux variation. Constant current will lead you to no output power at all.

2. Windings must not be placed in the gaps. That does not work. They just get burned due to gap losses.

Take into account that the current technology allows making Switch Mode Power Converters with efficiency recorda higher that 99% and size records. You cannot surpass that with low frequency magnetics.

Finally, as far as I can tell, the CR4 community are here because we are BORED and we have NO FRIENDS to talk about these things. We could not care lesa about stealing your ideas. We have our own as you will realise over time.

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#40

### Re: Generator

08/03/2017 9:48 AM

"Finally, as far as I can tell, the CR4 community are here because we are BORED and we have NO FRIENDS"

I'm both surprised and sorry to hear that! I have so many projects to work on that there is no way I could be bored, unless something prevented me from working on those projects. I have a number of very good friends, including at least one I met here on CR4.

I am here to help people solve problems. Isn't that what engineers do? I know that I have done that on several occasions.

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