Bare copper wiring for magnet charging

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Model T Ford Forum: Forum 2015: Bare copper wiring for magnet charging
Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Monday, December 29, 2014 - 07:02 pm:

This is going to sound pretty lame, but I'm going to put it out there anyway. I find that there is a lot I don't know and there are a lot of people posting here who do know!

I had someone bring 14 gauge solid copper wire over to me from the States to make a magnet charger like Robert Anderson made, but I forgot to specify that it should be insulated. So now I have bare wire to work with. If it is not insulated it will not create a magnetic field, right? So what would the easiest way be to insulate it? I have shrink wrap and red insulating spray.

Any better suggestions would be much appreciated.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John McGinnis in San Jose area, CA. on Monday, December 29, 2014 - 07:45 pm:

Spain must have suitable wire. I can't recommend anything reasonable or practical for insulating that 14 ga. wire. What you want is magnet wire, or wire with thin insulation. You can always parallel smaller gages if you need to to get the proper current/ampere turns. But for that matter, you only need a second to recharge a magnet, so use a higher voltage and a smaller ga. wire...so it gets warm and has a voltage drop...no matter.


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier on Monday, December 29, 2014 - 08:22 pm:

Eric, I built a charger a couple years ago by using pre wound coils from old metal halide light transformers. I bought the book on ebay by david gingery. I'm no electronic wiz by any means but was able to build his design with no problem. I think I ended up with about 20 bucks in the rig and it works great. KGB


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Monday, December 29, 2014 - 09:28 pm:

Eric,
Each winding has to be insulated from the other. If you have to use this wire, there are two possibilities;
1) coat it with some lacquer paint then wind the coils--this could be problematic, getting the insulating lacquer on evenly so it insulates well.
2) take strips of wax paper, put it under the wire was you wind it, and have the sides face up, insulating the wire from the piece right next to it. This will take time, but should work fine.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Conte on Monday, December 29, 2014 - 10:36 pm:

You could use a Mark IV Positron Force Field Unit; it would create an insulating shield around the entire length of the wire preventing the possibility of a short.
I think Granger has them on back order and does not know when they will become available so get insulated wire instead.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Monday, December 29, 2014 - 10:57 pm:

It takes about 17 feet of 12 house wire in a simple wind to put a charge I have lifted 15 pounds with. That's by pulling a magnet from a fixed plate and ends ground flat. It would probably take 20 feet of 14 wire. Using a battery with say 650 amps for power it heats the 12 wire fast with three or four bumps on a switch. So 14 wire would heat faster.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Monday, December 29, 2014 - 11:21 pm:

My strong advise is to not try any form of spray coating on the wire since internally you are almost for sure going to get a short in it and then the whole pile of wire is worthless as is your magnet charger. They call it MAGNET WIRE for a reason. Make a trade or get the right wire since it will otherwise be a lot of effort for naught. I have designed a lot of different transformers during my career and wound a fair number of prototype coils and transformers and I would never attempt to make a coil or transformer out of anything but the correct type and gauge of wire.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Clayton Swanson on Monday, December 29, 2014 - 11:56 pm:

in the mftca electrical book it says to use the windings out of two junk gm starter solenoids. solid wire, coated with sumthin i presume is what John is saying is magnet wire. the article describes to take the unit apart, and save only the heavy gauge wire, being careful not to damage it. old article, so i would guess we are talking about the 60's thru 80's vintage, they are mostly the same, and i know nothing of later gm stuff since i drive a honda now, and you dont have to know how to fix them, they just go and go


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Conte on Tuesday, December 30, 2014 - 12:11 am:

You can get magnet wire from Amazon and Mcmaster-Carr.


http://www.amazon.com/s/ref=sr_pg_2?rh=n%3A228013%2Ck%3Amagnet+wire&page=2&keywo rds=magnet+wire&ie=UTF8&qid=1419915934

http://www.mcmaster.com/#magnet-wire/=v8ra8v


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Tuesday, December 30, 2014 - 03:00 am:

"Magnet wire " insulation was originally invented by A. C. Gilbert (Yes, Mr. Erector Set) and was an enamel. Modern magnet wire insulation can be many different materials, some of it designed to melt at soldering temperatures, other to be good to 180 Celsius (used in aerospace applications). I too, would think you could buy regular insulated wire to make your recharger coils, but I have no idea what materials are commonly available in your area.
BTW, Clayton, Mid 90s Honda starters are notorious for giving you ONE warning that the starter solenoid is failing--but you can buy just the contacts, which is usually all that's wrong and change them without pulling the starter.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Tuesday, December 30, 2014 - 10:26 am:

I currently have a crude magnet charger made from solid core house wiring which I bought while visiting family in the USA. It works OK but I wanted to build something with a neater appearance and easier to use.

I have tried to locate insulated solid copper wire here in Spain, but since it is illegal for use in buildings it just isn't available. I have also tried to locate magnetic wire locally but to no avail. The "do it yourselfer" has a much better supply of materials in the States than in the rest of the world.

Mike, thanks for the info on Amazon. The 12 AWG looks like the best option so it will heat up less.



On the other hand, the Mark IV Positron Force Field Unit sounds pretty cool. I might just wait for that to come off backorder. :D

It's maddening to order items from outside the EEC. Firstly the international shipping rates are through the roof and then we get charged import duty of 30% of the merchandise value plus the shipping cost. What a racket. Guess I should be getting rich working in the Spanish customs department.

Thanks for the all your suggestions and info guys!


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Tuesday, December 30, 2014 - 12:30 pm:

Eric,
I have no idea why solid copper insulated wire is illegal there--it's the common wire used here! But if stranded wire is available, AFAIK, it will do the job too.
Guys, it sounds like, according to Spain, all our houses are dangerous and illegal!!!! Uh oh, and all you thought you had to worry about was aluminum wiring!
:-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Tuesday, December 30, 2014 - 01:38 pm:

The current color on 12 house wire is yellow for the outside of the cable. It has a higher heat resistance then the early white cable. Wire inside the cable is black-hot, white-neutral, and green-ground if its 110 volt.
Hear western Europe uses 220 volt where we often use 110 volt. Do not know if its true.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Tuesday, December 30, 2014 - 02:05 pm:

Everything is 220V here. Only copper strand wiring is used. No solid wire allowed.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Tuesday, December 30, 2014 - 02:17 pm:

It is also 50Hz rather than 60Hz hence motor driven items have to be considered for this before just plugging them in.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Tuesday, December 30, 2014 - 02:21 pm:

David, I am not sure why the solid wire is not used here either. It may not be a safety aspect but simply to make it easier to string the wiring through the flexible conduits inside the house. Most construction here is concrete, not drywall, so access to the wiring is quite difficult once the building is built.

I'll look into it and see if I can report back with something more official.

In the meantime, I'm now contemplating making the charger described in the Model T Electrical book (thanks Clayton). I have the book, but hadn't gotten to that section yet. That charger will work with loose magnets as well as magnets mounted to the flywheel (after removing the hogshead).


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Tuesday, December 30, 2014 - 02:24 pm:

Yes John. I had to leave behind a lot of my beloved antique electric fans and clocks when I moved here because the 50 Hz cycle just won't run them at the proper speed. The fan motors run noisy and overheat and you can imagine what the electric clocks do!


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Semprez-Templeton, CA on Tuesday, December 30, 2014 - 02:36 pm:

Stranded wire is just fine for your application. I am sure you can find # 14 or #12 stranded wire much cheaper in Spain.

I made my charging coils with #12 stranded wire because that's what I had. It works well.

We call stranded wire "machine tool" wire here because the NEC requires it's use for factory machinery etc. Vibration will cause solid wire to work harden and fracture... so they say.

It appears you are overthinking this issue a bit. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Tuesday, December 30, 2014 - 02:49 pm:

Well, shoot Eric, the clocks wouldn't even be right twice a day--unless you left them unplugged!! :-)
AC Gilbert sold 50 cycle transformers for their electric trains, both for the foreign market, and for the few places in the USA that still had 50 cycle current (apparently they were still around in the 1940s).
I do think you can get away with building your charger with stranded wire--any electrical engineers around to check this out. Over here, the solid wire is cheaper to buy than the stranded. I'm not up on commercial electrical code, but I think wire run inside conduit is supposed to be stranded--I do know that running romex wire in conduit is a no-no, something about heat build up inside the insulating sleeve cover.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Tuesday, December 30, 2014 - 03:06 pm:

Eric,

You seem to be trying to source this wire from the construction industry suppliers, as you mention building codes prohibiting the wire you're looking for. Even in the U.S. nobody in the building trades would have the wire you want. I would suggest you look for a source in the electronics industry. I have to believe that somewhere in Spain, someone is winding transformer coils and electric motors. I guarantee you that they're not using anything other than enamel insulated solid wire for those things. Does anyone in Spain, or elsewhere in Europe for that matter, rewind electric motors? If so, they would have a source for the wire you need.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Tuesday, December 30, 2014 - 03:11 pm:

Some thing I have wondered about John might be able to answer.
Say you used 6 or 8 wire that had ten strands
Then were able to get five turns on each leg of a T magnet. Forgot the formula but as I remember it takes 10K or 12K of ampere turns to charge a T magnet.
Does each strand count as a turn? or just the total of strands of the cable? Hope I explained this thought right!
As I remember Frank Fenton took heavy cable with only a few wraps using a battery and got a good charge.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Tuesday, December 30, 2014 - 04:54 pm:

I asked for wire for rewinding motors at a lot of electrical and electronics supply houses but no go. I think sometimes they just don't want to deal with someone who doesn't have an official installer's card.

I could swear I read on the forum that it HAD to be solid wire. If it's not necessary then I really have been barking up the wrong tree! I can get all the stranded wire I need right here. That's great news!! :-))


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Tuesday, December 30, 2014 - 04:57 pm:

David, I agree with you about the clocks. I could just leave them unplugged but being on time twice a day still isn't enough for me ;)


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Tuesday, December 30, 2014 - 11:40 pm:

One of the great advantages to "enameled" wire, is the little space the insulation takes up, allowing the winding assembly to be smaller. Prior to enamel insulation, motor wires were insulated with cotton cloth, which would also "burn through" easier than the enamel.
Since space isn't a big consideration for the magnet charger, using house wiring is only a cosmetic issue--I THINK!
Still asking: any electrical engineers here can tell us if stranded wire can be used instead of solid? Paul, I don't think each strand counts as a turn because they aren't insulated from each other--again we need some info from an electrical engineer type!!
Eric, glad you liked my clock joke--it's from an OLD Three Stooges movie!


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Semprez-Templeton, CA on Wednesday, December 31, 2014 - 01:27 am:

Stranded wire is just fine for this application. It will make no difference in the strength of the electro magnet AT ALL.

Eric you can buy machine tool wire at an industrial supply store... Think Grangers, or an electrical supply store where contractors buy their electrical gear here in the states. I would use wire with a 500 VAC or higher rated insulation as it will handle the heat better than automotive wire.

Each loop of wire = 1 turn. So if you make a coil with 100 turns and apply 90 amps your coil will produce 9000 amp turns (the magic number). Enameled wire is OK but not necessary. The only advantage to enameled wire is its ability to dissipate the heat a little better and it will produce a slightly smaller (tighter) coil.

I was an Electrical Engineer most of my career... if that means anything.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Wednesday, December 31, 2014 - 04:35 pm:

Thanks for the confirmation John. I appreciate you sharing your know-how!

My options for copper strand house wiring in Spain are 1.5, 2.5 and 4 sq mm sections.

For comparison the equivalent sections in AWG:
- 12 AWG has a 3.3 sq mm section.
- 13 AWG has a 2.6 sq mm section.
- 14 AWG has a 2.1 sq mm section.

The 4mm is really pretty thick and difficult to manage in small spirals. If I were to use the more common 2.5mm wire, it would be practically identical in section to 13 AWG.

Does this affect the number of turns necessary to reach the 9000 amp turns?

I'm sure this has appeared in a previous post, I remember reading about the minimum amp turns issue, but can you tell me why or how the 9000 amp turns works best?

The family calls and it's time to ring out 2014 and bring in 2015. I still have an hour and a half but probably won't be checking the Forum until "next year"!

HAPPY NEW YEAR!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Anthonie Boer on Thursday, January 01, 2015 - 04:57 am:

Eric in Spain .
For all of you ALL the best for 2015 .

Eric : Is this the wire you are looking for ?
It is 1mm DIAM. and the other is 1,6 mm DIAM.
It is solid wire and insulated .
If you need something please let me know,and I send it to you
1913R
1914R
1915R
Toon


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Thursday, January 01, 2015 - 06:51 am:

Happy New Year Toon!

Thanks for the offer. The 1.6mm diameter wire should be equivalent to 14 AWG (2.1 sq mm section) so it should work fine. It would make a much neater and more compact unit than the insulated house wiring.

I don't know how much I need yet to make the charger yet...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Thursday, January 01, 2015 - 10:41 am:

Commercial magnet chargers load a capacitor with a bunch of amps then dump it in a magnet to charge it in one hit. As long as you get ampere turns equal or above the 9000 mark it should be OK.
I think the reason early vintage chargers used so many wire turns with small wire is they had nothing that would produce high amps like a modern battery.
Charging magnets is not my area, just posting what was learned jumping through the hoops when it caught my interest!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Thursday, January 01, 2015 - 11:10 am:

One point learned with the wire wrap is confusion of north and south poles. I found that a length of gas welding wire bent in the shape of a T magnet stuck in the charger and magnetized then checked with a compass for proper pole location worked well no mater how they were wound.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Thursday, January 01, 2015 - 02:20 pm:

OK guys. I've spent half of the first day of the year rereading previous posts concerning how to and how much wire to use in a magnet recharging setup. I can now declare that I am totally confused about how much 14 AWG wire is really necessary in order to achieve the 9000 amp turns.

My idea is to create a charger similar to Robert Anderson's which appears in the following post: http://www.mtfca.com/discus/messages/411944/499231.html?1418063714

I would like to use a single 12 Volt battery. It's for a diesel engine so it gives fairly hefty amperage.

I would like to know:

Do I need to know the Volts and Amps available (number of batteries and their capacity) in order to calculate the number of wire turns? Robert Anderson used 60 turns of 14 AWG.

Would more wire turns than necessary create any problems?

Any more tips would be greatly appreciated. Thanks!

(Message edited by esole on January 01, 2015)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Anthonie Boer on Thursday, January 01, 2015 - 02:55 pm:

Eric S ; My first attemp to made a charger is on the picture, but this one was not strong enough .
Toon
1916R


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Thursday, January 01, 2015 - 03:22 pm:

Roberts set up looks good from personal experience. The only reason my 15 1/2 pounds was lifted with 12 wire is the ends of the magnet were ground flat for a larger area to lift with. The extra wraps Robert used are in the right place. 60 wraps times a battery with 500 amps equals 30K of ampere turns. Robert lifted 10 1/2 pounds with out grinding the ends. not bad at all.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Thursday, January 01, 2015 - 04:04 pm:

"...a battery with 500 amps..."

That's not how you calculate AT. How do you know that battery was supplying 500 amps to the coil? It may have been supplying 30 amps. The capacity of a battery has nothing to do with the supply current to the coil. The coil will draw current based on its resistance and the voltage of the battery.

Simplified:

Amps = Volts / Wire Ohms
AT = Amps x Turns


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Thursday, January 01, 2015 - 05:22 pm:

You are much sharper in many areas then I Ken!

I checked the turns on my dust collecting charger. It was 17 on each leg using 12 house wire.
Looked at my AutoZone battery in my Ford Van It states 750 cold cranking amps. The Tractor battery used four years ago was about that size.

Took a four year old T magnet charged four years past with just a slight grind on the ends setting on a plate ends down.

It still easily lifted an exact four pound weight with my hand and would be probably double that if tested in my test platform.

I thought with 2X17=34 34x750=22,500 that my total AT was 22,500

What was I likely getting?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Thursday, January 01, 2015 - 06:11 pm:

OK Ken, so my internet search tells me that 14 AWG has .25 Ohms resistance per 100 ft.

So:

10.8V / .25 Ohm = 2.7A draw on the 12V battery.
AT = 2.7A x 60 turns = 162

This falls quite short of the 9000 amp turns that John Semprez mentioned earlier.

I'm sure this a calculation error on my part. Maybe I am mixing apples and oranges by using the wrong terms?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Thursday, January 01, 2015 - 07:35 pm:

Eric - My chart says 2.58 ohms per 1000 ft. If your coils use 100 feet of wire, that's .258 ohms. (14ga.)

10.8v / .258 = 41.86 amps. (Well above the wire rating, I might add.)

41.86 x 60 turns = 2511.6 AT

This is enough to magnetize but will not achieve full saturation.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Thursday, January 01, 2015 - 07:51 pm:

I should mention that you should NOT let the coils get hot to the touch. As temperature goes up, so does the resistance. And as resistance goes up, amps go down. At 100 degrees, the current will drop to 36A. 36 x 60 turns = 2160 AT.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Thursday, January 01, 2015 - 08:00 pm:

Paul - All I know is that your wire will not draw 750A from your battery no matter how big the battery may be. If it did, all you would see is a bright flash and sparks flying every where. You need to know the resistance of your coil and battery voltage to know the current draw.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Anderson on Thursday, January 01, 2015 - 09:22 pm:

The higher capacity battery will not drop in voltage as much during a discharge. Mine dropped down to 10.8V; unfortunately I didn't record the capacity of the battery. I think as long as it can maintain 10V during the discharge it is big enough.

If the starting solenoid in your car is easily accessible, you can use your car's 12V starting circuit as your power supply. Just disconnect the cable going from the solenoid to the starter, attach one jumper cable to the output of the solenoid where the cable was, the other to neg on the battery. Hook up the other ends of the jumper cable to your magnet charger and use your ignition switch to activate your charger. The solenoid on my Ford Ranger was easily disconnected and it worked great.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Friday, January 02, 2015 - 08:39 am:

Probably not a good idea to use the starter circuit of a modern OBDII car. Disconnecting the starter can set several DTCs in the computer. The computer "sees" the start circuit engaged but doesn't get a timing pulse from the engine. Some models will also disable the fuel pump along with the DTC.

If you are flying by the seat of your pants, simply clamp an ammeter onto the battery cable feeding your magnet charger. Engage it and read the amps. Be sure to use a meter that can handle the range. The in-line digital meters normally handle only 10A. You'll most likely need one with a 100A range. Around 30A if you planed/designed your coils.

I repeat; CCA battery amps doesn't mean squat when it comes to the current drawn by your coils other than the battery's ability to supply that current. The "discharge cycle" is measured in milliseconds so even a motorcycle battery could be used if you wind your coils correctly.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Friday, January 02, 2015 - 10:51 am:

Interesting thread for me! Its great to have an idea where mistakes were made if a stock system is used on my Ts.

Beginning to think the early floor switch used to power my charger was an advantage because it only takes a 1/4 second bump for battery power for charging. If the switch was held down for a second or two the wire would cook.

I guess after four years the magnet charged still lifting twice what a piston weighs the saturation is not that bad but next time a few changes will be made if I live long enough.

Thanks Ken!

.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Friday, January 02, 2015 - 02:02 pm:

I based the saturation on the 9000AT figure. I don't know where that came from. Seems the saturation number changes every time one of these magnet charger threads comes up. I think I recall an old thread where 2500AT came up.

I'll leave the details to someone else but Ford suggests 36v for the in-car charging. The coils on the mag don't have many turns (I measured about 12' for the wire for each coil), and that seems to charge the magnets well enough to "work". So I'm not sure what the real AT point may be for saturation. It would be nice to have a target spec that everyone could shoot at instead of the constantly moving AT. I don't know of anyone that did an in-car charge then disassembled to check the strength/pull of the magnets. They just charge them and go riding. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Friday, January 02, 2015 - 06:07 pm:

If magnets were to be charged "in car", the data would be as such:
33 Volts (allowing for voltage drop) / .8 Ohms (measured on my newly rewound coil ring) = 41.25 Amps.
These Amps multiplied by 25 turns (aprox. on my old bare coil ring) = AT 937.5 which is 1/10th of the 9000 AT mentioned earlier.
This would account for the in-car charge not being sufficient to fully magnetize (so they say) but works at least for some time.

I charged some magnets a few months ago with my current charger setup which consists of 12 ft of solid copper 12 AWG "house type" wire with the thick insulation and no spacer bar connecting the magnet ends.
Calculations:
22 Volts (allowing for voltage drop) / .02 Ohms = 1100 Amps (theoretical; surely much lower. I didn't measure actual amps given by the two batteries)
These Amps multiplied by 29 turns = AT 31,900





Magnets got three zaps and hold between 5.5 and 6.0 lbs before pulling loose from an iron piston, measured with a fish scale.

This AT of 31,900 sounds just way too high to be true, so I suspect my calculations have slipped?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Robert Anderson on Friday, January 02, 2015 - 08:54 pm:

Looking good, Eric, your calculations look ok indicating you have way too much current flowing thru your coils. Its producing over 2400 watts of power, and will get the coils hot very quickly, if you haven't already found out. You don't need 2 batteries; just use one 12 V battery. You can also increase the resistance of your charger by putting more coils on your charger; you have plenty of room for more coils. Thats why I used 14 gauge wire; it seemed to be the "sweet spot" for total resistance given the space available for the coils.
Although my ongoing studies have found only slight benefit to storing magnets with keepers, I think its a good idea to have one across the poles when charging. I think it completes the magnetic circuit during charging. When I return home I'll test that theory as well.
There are two types of chargers; one like yours and mine that place the coils directly on the magnet to be charged, and the other kind which used a second magnet to produce a field thru the magnet that has its poles touching. The in car method uses that setup but is further hampered by the air gap between the two magnets. Most commercial chargers, including Ford's, are of the second type, but I'm not so sure its better, just more convenient.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Saturday, January 03, 2015 - 03:33 am:

This setup does get hot quickly indeed. It can do two or three magnets then needs to cool down. I liked the looks of your charger and figured it would be a lot easier to use with a solenoid instead of swiping the end of a wire with the resulting sparks flying.

I hadn't really given much thought to the magnet recharging process until this year. With the magnets off the flywheel it was the right time to charge them. I bought them from a vendor in 1989 and the magneto worked OK but they certainly wouldn't pick up a piston by any means.

I'm having fun with the recharging process and am learning a lot about magnets and magnetism. Thanks to everyone for your input!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Saturday, January 03, 2015 - 12:00 pm:

I don't see a switch on your system Eric. If you are striking the bare wire to the battery post or creating a spark that close to the battery it could be dangerous.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Saturday, January 03, 2015 - 03:11 pm:

Paul, you're right, I was striking the bare wire against a battery post clamp - way too near the battery.

My new setup will boast a real starter solenoid encased in a wood box - much safer.

Thanks for the heads up!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole - Castelldefels (Spain) on Sunday, January 04, 2015 - 01:07 pm:

I wasn't sure I had understood John Semprez's explanation of the Amp Turns concept, and not wanting to bore everyone with my ignorance I contacted him directly about it. The resulting answer cleared up a lot of things for me concerning magnet charging, and while many readers of this Forum are surely well versed in this elusive subject, that explanation appears below for other readers who might want a little more information, especially relating to the most effective way of winding the wire on the charger. The following text is courtesy of John Semprez.


The number "9000 amp turns" relates to the magnetic density created by an electro-magnet coil. It is this magnetic "power" that re-aligns the molecules in an iron bar permanent magnet. The goal is to have all the north pole (+) molecules aligned in the iron bar. In a plain (non magnetized) iron bar, the molecules will be arranged in a random manner so the +'s and -'s cancel each other out, and it is not magnetic.

The old Ford engineers determined that a coil producing "9000 amp/turns" of strength is optimal to fully charge (realign the north poles {+}'s) in a Ford magneto magnet. The amp turns number is just a ratio... so theoretically a coil of one turn with 9000 amps applied would be the same as a coil of 100 turns and 90 amps applied, or 200 turns and 45 amps applied. The reality is that there are losses associated with certain coil configurations, for example a coil with 10 loops wide and 10 loops deep will be less effective than a coil of 20 loops wide and 5 loops deep. This is because the farther from the core (in this case your Ford magnet) the windings are, the more the magnetic strength of the coil diminishes, but you should not be too concerned with these numbers.

So for practical purposes you will want to build a tight coil, as long as possible (as long as the magnet's leg) with as few loop layers as possible to achieve the amp/turns needed. The wire size will determine the maximum number of amps the wire can carry (how much resistance) it has.And the number of loops in your coil will determine the magnetic strength of the coil.

The hard work has been done for us, as we know a #12 wire has enough capacity to do the trick with 100 to 200 turns on our charging coil. Because the charging is done in short bursts, the heat will dissipate quickly, and since we also know the magnet alignment occurs instantaneously in the Iron, short bursts do the most work. Some people recommend lightly tapping the Ford magnet with a small hammer just before and just after each charge impulse to help the molecules align. I've tried both ways experiencing no real differences.

So in summary, if you build a coil with enough loops, and your battery provides the amperage necessary, your coil will produce the amp/turns required to effectively charge your magnets.

I hope I haven't totally confused you...but if I have, feel free to write me back.

Regards, John


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