Author Topic: Trying to fabricate electromagnet, requesting help please  (Read 14405 times)

Offline burnit0017

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Hi, I am trying to fabricate a electromagnet. What is the recommended method for cutting the pocket for the coil to sit in? I tried a boring tool but destroyed the tool. 

Offline Bearcar1

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #1 on: July 19, 2014, 12:07:43 PM »
Hi Burnit', does the part have to be one piece? Consider making it in two or perhaps three separate pieces and silver solder them together. That is make the 'cup' for the magnet to nest in and then turn up a 'slug' to fit the center and secure with a screw from the back. Just an idea. otherwise trepanning a deep, narrow slot such as that will take some doing. Getting a cutter ground correctly is the trick.


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Jim

Offline Admiral_dk

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #2 on: July 19, 2014, 12:13:06 PM »
You can get special tools for that - a special kind of boring bar that is curved and you might be able to grind a tool yourself that does not touch the object with anything but the cutting edge, but s normal boring bar will not do.

Offline sshire

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #3 on: July 19, 2014, 12:32:05 PM »
Agree that fabricating is easier and would save a lot of metal that would otherwise become chips.  You could also use an end mill a bit larger than the boring bar to create the starting hole and go from there. Once the pocket is bored out, the center post could be screwed in from the backside.
Best,
Stan

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #4 on: July 19, 2014, 12:32:47 PM »
Hi, thanks for the help. Making it from multiple pieces seems like a great idea. Most of the time the obvious solutions eludes me. :facepalm:
I will give it a try and post results.  Working on large beam style engine to drive a permanent magnet alternator. Thanks again.

I have seen other projects with a small size electromagnet have 100's of pounds of pull force using only a couple of D cells. 

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #5 on: July 19, 2014, 03:35:00 PM »



Boring coil pocket and funky DIY steady rest.

Offline smfr

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #6 on: July 19, 2014, 05:04:13 PM »
Another option would be to mill the slot on the rotary table.

Simon

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #7 on: July 19, 2014, 05:14:05 PM »
Hi, thanks for info. Making it from two pieces will allow me to turn the coil on the center and then mount the center using a center bolt. It will be easier for me to fabricate. I used a old broken roughing mill end to do the boring, the method worked really well from me. Thank you for all the info.

Offline ths

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #8 on: July 19, 2014, 09:19:35 PM »
That really is a funky steady rest. Does it work OK? Hugh.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #9 on: July 19, 2014, 10:58:22 PM »
Hi, it helps and it does stop the work piece from flying across the room. If it starts to wobble, I stop immediately. It is a first attempt and needs improvement.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #10 on: July 20, 2014, 04:28:26 AM »







I still have to add coil.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #11 on: July 23, 2014, 02:50:21 AM »




Hi, Icompleted the fabrication. Thank you to everyone for the help.




Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #12 on: July 23, 2014, 06:30:30 PM »
<a href="http://www.youtube.com/watch?v=TDmv59p1XkA" target="_blank">http://www.youtube.com/watch?v=TDmv59p1XkA</a>


video showing results, fabricated a second EMag, wired two EMags is series, powered by 100 volt pulse from 7800 uF capacitor :zap:

Offline Bearcar1

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #13 on: July 23, 2014, 07:03:25 PM »
Looks like your EM's have a bit of oomph in them, what pray tell are you erecting them for if I could be nosey? It reminds me of the many maglocks I have installed on security doors. Quiet, efficient AND silent.


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Jim

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #14 on: July 23, 2014, 07:26:42 PM »
Hi, I am working on a gravity assisted torque converter to drive a permanent magnet alternator to generate small scale electricity. Looking for a way to include positive feedback into the system. I may have to add a solar panel, 12 volt battery, and voltage multiplier circuit, to keep it running. It just a experiment at this point, but I can't stop thinking about. If I can't get it working after this, then I can move on.

Offline Bearcar1

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #15 on: July 24, 2014, 03:06:44 AM »
That sounds interesting, keep us posted with your progress.


BC1
Jim

Offline derekwarner_decoy

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #16 on: July 24, 2014, 04:27:25 AM »
 :old: ...."poles apart"  :LittleDevil: ....Derek
Derek Warner - Honorary Secretary [Retired]
Illawarra Live Steamers Co-op - Australia
www.ils.org.au

Offline nick

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #17 on: July 24, 2014, 08:14:18 AM »
I wound up a coil as a demonstrator for electromagnetism, it did work, but there were 2 'by products', heat (loads of it) and it hummed. I was using a bench power supply, the voltage was altered with a potentiometer, as I altered the voltage, the tone of the 'hum' altered. I could onkly have it on for a minute at the most before it got too hot.......
Who I am is best not discussed, for I have been many things in my time.....

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #18 on: July 24, 2014, 11:52:14 AM »
Hi, for continuous duty, you have to limit the current. On my project I am just charging a capacitor and applying one pulse once per revolution. Thanks for info.

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #19 on: July 24, 2014, 02:25:32 PM »
Anti-gravity machine?

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #20 on: July 24, 2014, 02:54:16 PM »
Hi, gravity assisted device. OverUnity is NOT possible. It will never produce more power than is being supplied from the output shaft. A step down DC to DC buck converter at the output of the PMA running at < 50% duty cycle removes the braking effect created from the back EMF. It is a basic MPPT circuit that works with a Permanent magnet alternator.

Video of circuit driving a 50 watt load, without the circuit I was unable to turn the PMA.
 
list=UUE--_X1h08StIiaSSxefTCg


I view generating electricity like pumping water. So using the MPPT circuit with mechanical advantage is the approach I am using. Again this is just a experiment. I will post results if and when I can get it to work. Thanks for showing interest. Cheers :stir:

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #21 on: July 24, 2014, 05:02:24 PM »
What is the goal?

Greg

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #22 on: July 25, 2014, 12:14:58 AM »

Hi, I am working on a similar project for generating electricity.

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #23 on: July 25, 2014, 12:36:14 PM »
It's unfortunate those people have no idea what they are experiencing. They'd be better off replacing the pendulum mess with a flywheel. The direct operating demonstration of how difficult the work is, is wonderfully flawed. The length of the arm might be the same, but when he's swinging the pendulum by the crank arm he has Pi*D of distance as opposed to a few inches, the true length of the lever on the pendulum is much larger. I'm sure someone has told them, but it doesn't fit their agenda or business model. Simply adding a second mass to balance the other one would make it even easier to operate because gravity isn't helping at all.

Greg

Offline Admiral_dk

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #24 on: July 25, 2014, 08:14:10 PM »
Nice idea - but it's kind of made already ....

http://en.wikipedia.org/wiki/Hydraulic_ram

This one only works on flowing water, so It would be nice for a similar device to fit a well. On the other hand - they do exist as simple windmills. Making one that runs on solar power is a good idea.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #25 on: July 26, 2014, 08:27:17 PM »
<a href="http://www.youtube.com/watch?v=ktM0sDQnmpo" target="_blank">http://www.youtube.com/watch?v=ktM0sDQnmpo</a>
video showing manual operation

Hi, I fabricated a quick frame to identify the problem areas. The biggest problem is I need the electromagnets to trigger at 0 and 180 degrees. The mechanism will only allow for triggering at at 90 and 270 degrees. Is there a mechanical configuration that I can use that will help or allow the trigger location to shift 90 degrees.  The electromagnet are pulsed with power so they are on for only a short time. . 

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #26 on: July 27, 2014, 11:14:24 PM »
<a href="http://www.youtube.com/watch?v=SaHEUQdmbRs" target="_blank">http://www.youtube.com/watch?v=SaHEUQdmbRs</a>

Hi, I found a configuration that may solve my problem. I will try replacing the pistons with the electromagnets.

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #27 on: July 28, 2014, 03:04:23 AM »
That brushless motor you're using as a generator could be up to 80 or 85 percent efficient. Anything connected to it that results in power loss reduces that. This includes the bearings, gears, any reciprocating mass, and I'm not even sure where the electromagnets come into play.

If we agree that greater that unity is not possible and the generator being used is ~80% what is the projected efficiency of the device you're building?

Greg

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #28 on: July 28, 2014, 10:48:11 AM »


Hi, I am experimenting with gravity assisted power. The final configuration will have a flywheel with shifting weights. The PMA will charge a large capacitor that will provide power to the electromagnets once per revolution. The movable weight on the flywheel will shift toward the center on half of the revolution creating a over balanced wheel. So I am testing to determine if the combination of the flywheel configuration and the feedback from the electromagnets will produce a working device. If not I can add a external power source or replace the electromagnets with steam cylinders. Again this is just a experiment.

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #29 on: July 28, 2014, 01:23:54 PM »
Do you understand why the pump you posted has no help from gravity?

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #30 on: July 28, 2014, 04:20:58 PM »
Hi, I am still thinking about it, why :slap:

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #31 on: July 29, 2014, 04:27:08 AM »
For gravity to provide "free" energy, the  potential energy must come from outside the system. For example, a river with a damn and power plant uses gravity to generate electricity. The energy to lift the water upstream came from the sun which evaporated surface water to clouds which fell as rain or snow at higher elevation than the power plant. In the pump video you have to lift the pendulum, so you are adding that potential energy yourself. By eliminating the pendulum and using the same mass to create a flywheel the pump would be even easier to use. The amount of energy stored in the pendulum at that height is very small. The ease of pumping with the large crank comes, as I said before, from the working distance of the crank which is probably 30-60 times the distance the lever moves when he moves it directly by hand. Either the inventor doesn't see the mistake they've made or they are taking advantage of people who can't see it. It's that simple. Unfortunately, there is a lot of this, some unknowingly propose products like this, others intentionally and use gimmicks to sell them.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #32 on: July 29, 2014, 09:44:23 AM »
Hi, interesting, I view it as a gravity assisted torque converter. To fabricate a flywheel with the same effect would just increase the cost. I do not work there so there is no problem here. I guess it all comes down to how you analyze the device. Thanks for your input.
« Last Edit: July 29, 2014, 12:35:02 PM by burnit0017 »

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #33 on: July 29, 2014, 03:26:01 PM »
I guess it all comes down to how you analyze the device.

Which is why I asked about your analysis of efficiency for your device. If you're trying to generate electricity, adding a electromagnet (obviously with less than 100% efficiency) to the system only reduces the output.

IMHO, physics allows only one interpretation. There is a reason most of these "ground breaking" devices never make it. And, it's not gov't conspiracy. It takes a fair bit of understanding of physics, electricity, mechanics, etc. to realize why these devices are either gimmicks or don't work as advertised.

A pendulum is just an unbalanced flywheel. Pendulums have applications, but this isn't a good one. A flywheel or pendulum is an energy storage device. You have to put energy in to get it out. How much you get back out depends on losses. That pump doesn't even need a flywheel, because there really is no need to store any energy between pump strokes.

Greg

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #34 on: July 29, 2014, 04:19:47 PM »
Hi, Thanks for the info. Basically I am experimenting to determine if the combination of this flywheel with shifting weights and feedback from the electromagnet will be of any benefit. I am not trying to develope any ground braking device or brake the laws of physics. This is just a experiment for myself and I received a request to post my progress.  There is nothing to argue about, overunity is not possible. Thanks again for the input. Cheers.   



Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #35 on: July 29, 2014, 04:58:04 PM »
Of course, carry on.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #36 on: August 01, 2014, 01:39:20 AM »
Thanks. Sadly the geometry of machine is not working well for the electromagnets. The electromagnet when mounted are stopping full rotation. But is not a wasted effort, I plan to install a steam cylinder and I use the PMA to charge some batteries. Thanks again for all the help. I hope to have something operating before it snows. Cheers

Offline PStechPaul

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #37 on: August 01, 2014, 09:11:49 AM »
Interesting, but except as an educational experience, I'm afraid that it will not result in anything practical or beneficial. There is a thread on DIYelectricCar that seemed to involve something possibly similar, at least having an electromagnet:
http://www.diyelectriccar.com/forums/showthread.php/help-circuit-open-source-development-85070.html

I think the video on the water pump stated that it would pump 1000 gallons per hour, which seems like a lot, but that's less than 17 gallons a minute, and the pressure gauge was reading only 20 PSI, which does not require much force. If the water does not need to be lifted very high, this would be a rather small amount of power. The website gives more details:
http://gravityassistedpower.com/our%20products.htm

One clue is the 1 HP electric motor option. It is virtually impossible for even a superlatively strong human to provide 1 HP (it's even difficult for a horse), and not for any more than a few minutes. See:
http://en.wikipedia.org/wiki/Horsepower

The amount of power required to lift 17 gallons of water to a height of 15 feet in one minute is:

17 * 8 * 15 / 32572, or 0.063 HP

You can also imagine how much effort it would take to lift 68 1 gallon jugs of water from the ground to a four foot loading dock, in one minute. It would be an effort, but not too hard to do one per second.

The formula for a reciprocating pump is:

HP = GPM * PSI / 1550, so for 20 PSI and 17 GPM this comes to 0.22 HP.

So, I am not much impressed...  ::) :Lol:

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #38 on: August 01, 2014, 12:30:37 PM »
Hi, hypothetically speaking, a natural disaster hits and wipes out everything. What is your solution? :thinking:

Offline PStechPaul

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #39 on: August 01, 2014, 11:32:09 PM »
It is unlikely for there to be a natural disaster that "wipes out everything", but it can (and has) happened on a local basis at an apparently increasing frequency and scale of damage, probably due to climate change. Mostly we have had to deal with failures of the infrastructure, electricity, natural gas, water lines, roads, and bridges, but in general these are conveniences we have become accustomed to having 24/7. Where I am, at least, there is plenty of water within a short walk, and there are ways to filter it or process it to make it safe. As I showed above, it is not necessary to have a "gravity assisted" pump to obtain water. The old fashioned hand operated well pumps are efficient enough and one person can easily pump enough water in a few minutes to provide for a family's daily needs.

As for the electricity, it is really just a modern convenience, and the Amish and many "primitive" societies do well enough without it. But there are many ways to make electricity, using free renewable resources such as solar, wind, and biomass.

The only thing that may be a difficult problem in the case of a widespread disaster is food. Those with knowledge can forage for food and use primitive but effective weapons or traps to obtain meat. Many people have their own (or communal) gardens where they can grow what they need, and various methods of storage outside the growing season. But unless there is a complete collapse of civilization (or extreme conditions such as warfare and genocide), eventually those who are not affected will be able to supply at least basic food (such as rice and beans) to those who have been wiped out.

So I question why you have asked your question, as it seems to be related to your "gravity assisted" devices. Tell us why they might be necessary.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #40 on: August 02, 2014, 12:38:50 AM »
Hi, at my location wind is not always available. Solar is expensive and is not always available. At my location, steam power is a good option.
I am not trying to sell anything, I am just exploring gravity assisted power as another option. I agree with your observation, generating more than 1 HP is not as easy as I first thought. Thanks for your thoughts.   

Offline Ian S C

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #41 on: August 02, 2014, 02:26:01 PM »
The nearest I'v had to a disaster was an earthquake September four years ago, the power was off for a few days at my place, and one of my hot air engines with a generator supplied power for a radio over that time, saving on batteries.      Ian S C

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #42 on: August 02, 2014, 03:03:10 PM »
Hi, are you using a MPPT circuit with the generator?


<a href="http://www.youtube.com/watch?v=tjhrZ5DuggQ" target="_blank">http://www.youtube.com/watch?v=tjhrZ5DuggQ</a>


I found this project with a Neo piston, it may be the solution I am searching for.

Offline PStechPaul

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #43 on: August 02, 2014, 09:43:48 PM »
A Maximum Power Point Tracking (MPPT) circuit might be useful for such things as solar cells, but I think a generator might be most fully utilized by adjusting the speed of the prime mover. The linear piston generator in the video is similar to the "shake" type flashlights that were popular for a while. I bought a couple at a Chinese Cheap table at a flea market and they would be better described as "shake-and-fake". because they just had a few dozen turns of fine wire on a cylinder that contained a slug of steel (not even a magnet), and the circuit board didn't have any useful components. The LED was connected to a couple of coin cells and they provided the energy until they died. It seemed to get brighter when shaken, but probably because it vibrated the connections and briefly reduced the resistance.



This is basically a device that uses Faraday's Law where a magnetic field moving in relation to a conductor generates a voltage (and current if the circuit is closed). There seems to be a patent for this although the principles seem to be pretty obvious:
http://www.google.com/patents/US5818132

Here is some information about linear generators and application to a Stirling engine:
http://adsabs.harvard.edu/abs/1982iece.conf.1862S

You may like this article because it claims over-unity efficiency.
http://www.e-ijaet.org/media/0001/87I8-IJAET0805863-DESIGN-AND-DEVELOPMENT.pdf

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #44 on: August 02, 2014, 11:31:08 PM »
<a href="http://www.youtube.com/watch?v=B3dLzZZ5jKQ" target="_blank">http://www.youtube.com/watch?v=B3dLzZZ5jKQ</a>


Hi, I found out the MPPT circuit for a solar panel will not work with a permanent magnet alternator. I took the core of the circuit which is a DC to DC step down converter and added a manually adjustable variable duty cycle. I found that by keeping the duty cycle below 50% it works really well with a PMA and removes the braking effect created from the back EMF.

Thank you for the additional information

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #45 on: August 03, 2014, 03:36:06 PM »
<a href="http://www.youtube.com/watch?v=yjOdNuXGrJM" target="_blank">http://www.youtube.com/watch?v=yjOdNuXGrJM</a>


Hi, first test of magnet piston. Promising results, proceeding with the rest of fabrication.

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #46 on: August 03, 2014, 08:58:21 PM »
I found that by keeping the duty cycle below 50% it works really well with a PMA and removes the braking effect created from the back EMF.

It doesn't remove back EMF. It can't. The best you can hope for is it converts the generated voltage to a more suitable load voltage with loss of efficiency. This makes it appear as though it's easier to turn the generator. This is strictly due to mismatch of the generator and load. You'll find the most efficient generator system has no voltage regulators or transformers. Boost converters for solar exists for the same reason. The panel voltage doesn't match the battery voltage, so it's worth a few percent loss in conversion to get the panel operating at maximum efficiency. This is great when the sun provides power for free. If you're turning a generator by hand, you don't want additional losses through conversion.

Greg

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #47 on: August 03, 2014, 09:17:41 PM »
Hi, thanks the for info. Without the circuit I could not even turn the generator using the same load.



This not my project but it shows the benefits of the same type circuit.
<a href="http://www.youtube.com/watch?v=0TE38SOdf64" target="_blank">http://www.youtube.com/watch?v=0TE38SOdf64</a>
« Last Edit: August 03, 2014, 09:23:08 PM by burnit0017 »

Offline dieselpilot

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #48 on: August 03, 2014, 10:31:31 PM »
Like I said, load mismatch. The simple, efficient, and cheap solution? A 6USD, 120V LED bulb. I replaced my 50W GU10 bulbs with 9W LED's and couldn't be happier. With wide input range on the power supply these bulbs operate from 80-250VAC.

There is a reason for everything, but it takes a lot of education and research. Now, if your intent is grid tie generation, MPPT complexity, loss, and cost is worth it, maybe.

Greg

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #49 on: August 03, 2014, 10:55:59 PM »
Hi, no, I  just plan to use it just for charging batteries, off grid. I am using a F&P that will generate approximately 1 volt per RPM, so matching the load is not possible. The circuit works well for my application. Cheers.   
« Last Edit: August 03, 2014, 11:19:20 PM by burnit0017 »

Offline PStechPaul

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #50 on: August 03, 2014, 11:33:58 PM »
The reason the alternator is hard to crank with direct connection to the load is caused by the non-linear resistance of an incandescent lamp. The 48W 12V bulb has a resistance of about 4 ohms at 12V, but below incandescence, it can be about ten to fifteen times lower. So with the cold filament, you will be pushing not the 4 amps you might expect, but (at least momentarily) as much as 40 amps, and since current is proportional to torque, you will have to strain ten times harder until the lamp starts to glow. This is the well-known "incandescent tungsten" load. I have seen this error in another video where someone measured the cold resistance of a lamp and then used that to determine that he was generating a lot more power than he was putting in.

http://en.wikipedia.org/wiki/Incandescent_light_bulb

Your buck converter or MPPT circuit probably has built-in current limiting so it will never try to output the current needed to power the load at low RPM, but it does charge its energy storage capacitor. Once that voltage becomes high enough it will dump its energy into the load and it will start to glow, so the current will drop. Eventually you will have it at full incandescence where it will dissipate about 48 watts and if your circuit has typical efficiency of 90%, you will be exerting about 55 watts of power on the crank, and the energy storage of the circuit components will smooth out the variations in torque (torque ripple) that is typical of single phase alternators (but less so for three phase, which is what most automotive alternators are). Automotive alternators are typically rather cheaply built and have poor efficiency, perhaps 50-75% at best, so they are a poor choice for wind power.

Another thing to consider is that a MPPT circuit does not necessarily result in maximum efficiency. The maximum power point for an alternator and similar devices occurs at a point where the power lost in the device is equal to that transferred to the load. Think of it as a 12V battery and a 1 ohm resistor. If you have a 12 ohm load the total resistance will be 13 ohms and the current will be 12/13 or 0.92A, and the load power will be 10.4W while the generator dissipates 0.85W and efficiency will be about 93%. If you have a 0.5 ohm load the total resistance is 1.5 ohms and the current will be 12/1.5 = 8A. The load power will be 0.5*8^2=32W, and the generator will have losses of 64W, for efficiency of 33%. For maximum power, the load should be 1 ohm, where current will be 12/2=6A, output power is 36W, and efficiency is 50%.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #51 on: August 04, 2014, 09:56:24 AM »
Hi, thanks for the input. I always viewed it as with the circuit I am sending current to the load. Without the circuit I am generating heat at the PMA and cooking the generator. I only know of two US companies that offer a MPPT circuit that will work with a permanent magnet alternator. On my circuit ; which is  basic; the output current is only controlled by varying the duty cycle. Nice observation about charging the input cap. Thanks again.
« Last Edit: August 04, 2014, 10:13:13 AM by burnit0017 »

Offline Ian S C

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #52 on: August 04, 2014, 02:41:16 PM »
Don't know if this has any relevance, this is a free piston Stirling Engine, the magnets are ex micro wave oven,  and the coils are old chokes from power supplies.   Ian S C  Ooops got a wrong one there, that's a Neuport 24 replica powered by an Australian built Rotec radial of 150 hp.
« Last Edit: August 04, 2014, 02:53:06 PM by Ian S C »

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #53 on: August 04, 2014, 04:44:54 PM »
Hi, great looking plane, I am interested in the Stirling Engine. Is there a thread started, will it work with a wood fire. I always wanted to try to fabricate a Alpha, but at that time I did not have my modest collection of machine tools.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #54 on: August 17, 2014, 12:22:35 AM »










Hi, just some quick photos showing progress. I hope to be testing in few days.

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #55 on: August 18, 2014, 02:11:57 PM »
Hi, I have completed my experiment.
Results:
I was not able to generate enough stored power at the capacitor for self operation.
It was great learning experience in that I was able to gain a good physical sense of how the configuration operates when both sides are balanced and now I have building block for a larger steam engine. Thanks for all the comments and help.   

Offline Ian S C

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #56 on: August 18, 2014, 03:03:13 PM »
     The Neuport is powered by the 9 cylinder(I think) Australian built radial, I think there was something about the original cylinders being ex VW, but I think they make their own now.  The aircraft is a Microlight, the owner had a heart attack a year or so ago and lost his PPL but wanted to keep flying. The plane started life in the USA.
      The hot air engine is a GAMMA type, fuel with LPG.  The power piston is a bit of cast iron about 3" long X 1 1/4" diameter(heavy piston is required).  Under the magnet on the piston is another with the like pole facing up to repel the piston there by acting as a spring,  When first built I did use springs.  The displacer has a fat rod, and works as a Ringbom type motor.  This motor could be run on solar power, although I have not tried as yet.       Ian S C
 

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #57 on: August 18, 2014, 03:27:30 PM »
Hi, what is the RPM? What are you using for lubrication?

Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #58 on: December 26, 2014, 02:50:47 AM »

Hi, I fabricate a pulse motor using the electromagnet. Needs improvement but it is working. :insane: It will also function as a test fixture.

Happy hoilday...

Offline PStechPaul

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #59 on: December 26, 2014, 04:44:24 AM »
I'm not sure exactly what you are trying to accomplish, but this looks like a switched reluctance motor (SRM). I have done some research on them and they have a great deal of promise. I made one with four lobes on the rotor and six electromagnets which are switched on and off and with switched polarity at a rate determined by timing from a PIC. It is not self-starting, but once it gets "in synch" it has a reasonable amount of torque. I may have presented this before, but have a look at my video. This is part 1, and I have plans to make a more powerful and possibly practical motor in the future using similar techniques:


Offline burnit0017

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Re: Trying to fabricate electromagnet, requesting help please
« Reply #60 on: December 26, 2014, 11:51:08 AM »
Hi, thanks for posting your project. I am working on a gravity assisted project to generate small scale electricity.The idea is to combine mechanical advantage, gravity,with a small amount of electricity at the input  It is probably not going to work but it is all in good fun. The worst thing that will happen is I will have nice piece of kinetic art. Thanks again and happy new year. 





using bench power supply at 18 volts, 0.35 amps, max RPM 240
« Last Edit: December 26, 2014, 02:45:29 PM by burnit0017 »