Magneto Charger Core Pieces

Jeremy Hartle

Subscriber
Whats best for a magneto charger. Solid cores or multiple pieces. I am going to build one and only want to do it once. I am shooting for around 40,000 ampre turns so should cover anything ill need.
 

Scotty 2

New member
Re: Magneto charger core pieces

Hello Jeremy
I've always been of the belief that solid cores is the way to go.
If your going to build one I'd recommend getting the book entitled "How to build a Magneto Magnetizer" by David Gingery.
Cheers Scott
 

Pat Barrett

Subscriber
Re: Magneto charger core pieces

I've heard them speak of using "Dead Iron" No one has ever said what it is or where else it's used or where to find it. I assume it's iron that doesn't retain magnetism.
 

Jeremy Hartle

Subscriber
Re: Magneto charger core pieces

Ok so is soft iron the same as mild steel. I have looked at the ginery book but appears to be out of production.
 

landreo

New member
Re: Magneto charger core pieces

Solid is better.

Mild steel and soft iron are not the same. Soft iron has a carbon content of around 0.3 percent or less. Mild steel is around 3 to 6 times higher. Mild steel, 1018 or 1008, will work fine and will be easier to find. True soft iron likely will be much more expensive.
 

Scotty 2

New member
Re: Magneto charger core pieces

Solid is better.

Mild steel and soft iron are not the same. Soft iron has a carbon content of around 0.3 percent or less. Mild steel is around 3 to 6 times higher.
Thanks for that. :)
It makes sense when you think about it. Less carbon = more room for magnetic stuff getting pushed around.

Cheers and ta
Scott
 

Jeremy Hartle

Subscriber
Re: Magneto charger core pieces

Mcmaster carr got low carbon steel in the .13 to.20 percent crabon. If this is to high where might one find this .03 carbon steel.
 

Jeremy Hartle

Subscriber
Re: Magneto charger core pieces

Bought some 2" cold rolled steel for the cores. I found 10lb spools of 18 gauge enameled wire. Ginery calls for 6 lbs per coil. According to my sipchering the amp draw went down by adding turns. Am i messing up going with bigger coils?
 

cobbadog

New member
Re: Magneto charger core pieces

From what I remember from some articles I've read you can reduce the strength of the magnetiser by adding too much wire.
Somewhere there is a formula for working out weight or length of different gauge wires and how much is recomended to be wound onto each core.

Hopefully someone with far more knowledge will set us straight.
 

DieselAddicted

Subscriber
Re: Magneto charger core pieces

I used 1018 cold rolled for mine and it works very well. I followed a proven home build design and did a build up thread here that you should be able to find via search. I will caution you that if you build a good one to be mindfull of what is near it. I carelessly left a wrench near mine am very glad that none of my fingers were between it and the pole it stuck to!!!
 

Scotty 2

New member
Re: Magneto charger core pieces

According to my sipchering the amp draw went down by adding turns. Am i messing up going with bigger coils?
The important factor is the ampere turns figure. By adding wire but you gain a heap of turns. The math needs to be done for current.

Cheers Scott
 

landreo

New member
I have no idea of your plans but I can make a few generic comments.

2 inch cores should be fine for tungsten steel horseshoe magnets or the flat Wico EK mags. No so much for alnico magnets.

You do not want any sharp edges in the magnetic path and the base should be the same size as the core and should not be larger so that none of the base will be outside of the core pieces. So for a 2 inch core, the base should be 2 inches thick and stop at the outside edges of the core diameter. Your base looks to be 1 inch thick and much longer and wider than it needs to be. You will loose around 0.1 to 0.2 Tesla from those sharp long edges and the thin base.

I ran a few quick simulations based on what I could see using 8 amps through 5000 turns on each core. That will give around 1.8 Tesla if you have good adapters to the magneto magnets. With poor fitting adapters you may drop to less than 0.5 Tesla which is not enough. Good fitting adapters are as important as the rest of the charger.

It looks good depending on what you are planning to charge. I'm am looking forward to more build photos and the final results.
 

Jeremy Hartle

Subscriber
This is all based off of Ginery's plans from his book. If its gonna be to puny i need to know now before i go any further. I want one that will charge anything i will ever need to. I'm not gonna mess with aircraft mags just tractors and engines.
 
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