Design Your Own Magnet Charger
Mar 11, · Joe shows us how to make a strong electromagnet with a elvalladolid.com's Going On:When electricity moves through a wire, it creates a magnetic field. We wrapp. Jun 15, · in this tutorial ill be teaching you how to model, texture, lighting and render a horseshoe magnet in maya
This is Part 1 of a 2 part series. Part 2 describes the machining of the magnet charger. While a friend of mine had a magnet charger, I always felt a little uneasy about putting him to the trouble of ensuring that the battery that powered it what to bring to hot yoga class fully charged and the fact he had to clear his work bench to make room to use it.
Part of the satisfaction I gain from restoring engines arises from the turning of various bits of metal into a working piece of machinery, so I felt that to make a charger would be a new how to make a horseshoe magnet, and that I would also learn something in the process. I knew little about electricity, apart from being able to change a plug, and knew even less about magnetism.
Fortunately, I still met my old school physics teacher for a glass of beer most weeks, as we were both members of a local rifle club, more social members now with failing eyesight! Next, I searched SmokStak. There was also reference to a Dave Gingery design. This was fine but I was no further along as I now had three schemes, each one using different size cores, all of which were, according to numerous people, successful. The only common point that I was able to identify was that 20, ampere-turns of copper wire appeared to be the magic number to achieve the full charging of a magneto.
Ampere-turns refer to the number of turns of wire around the core multiplied by the amperes that the length of wire draws. The first decision was to identify the optimum core size before calculating the gauge and amount of wire to wind around this, along with the power source to achieve the desired result.
I hit gold dust, as Martin was only too willing to help. He knew the subject of magnetos inside and out, and had built his own charger. Furthermore, he had some information he would photocopy for me about a charger built by Warwick Bryce and featured in Stationary Engine in It soon became apparent that I needed to understand a little more about the difficult subject of magnetism before designing my own charger in order to be satisfied that it would meet my future needs.
So again, I approached my old teacher, who subsequently proved most helpful. While I could have simply described the charger I built and how I achieved it, this would not be much help to anyone else wanting to build a charger to a how to make a horseshoe magnet specification and also understand a small element of the theory.
Magnetism My initial knowledge of magnetism was based on my school days when, as kids, we played with them. This knowledge was limited to the fact that a magnet had a north and south pole, other ferrous metals could be magnetized with the magnet and that like poles on the magnet repelled while opposites attracted each other.
Magnet steel Up to the s, horseshoe magnets were made from the toughest steel then available, tungsten steel. Since then, other strongly magnetic steels have been made, containing chromium and nickel up and until the s when compressed metal powders such as alnico and Alcomax were used.
Alnico consists of aluminium, nickel and cobalt, hence the name. These special high-energy magnetic materials are much more expensive than tungsten steel but they hold more than 20 times the magnetic energy. The tungsten magnets had to be long and thin to prevent alaska became the 50th state in what year de-magnetism, hence the large horse shoe magnets seen on the early magnetos, more compact magnets and magnetos being made when the new materials were available.
The downside to the later, non-tungsten, magnets is that they require a greater magnetic force to charge, but once they are fully charged, they create a stronger magnet.
Metals that can be strongly magnetized such as iron, nickel and cobalt are known as ferromagnetic, exhibiting a large attraction to magnetic fields and have a high ability to retain magnetic properties once the external field has been removed. They all get their strong magnetic properties through the presence of what is known as magnetic domains.
Magnetic domains Within ferromagnetic materials, the atoms tend to have their own magnetic field, created by electrons that circle it. Small groups of atoms, consisting of more than a trillion, tend to align themselves in the same direction and these groups are known as domains. Each domain has its own north and south pole, and in an un-magnetized state, the poles of the domains point in different, random directions with the result being that little or no magnetic force is displayed as they cancel each other out.
Placing magnetic material in a strong external magnetic field or passing an electric current through it results in the domains starting to align themselves in the same direction so the material starts to exhibit a stronger magnetic capability. The greater the magnetic force applied, the more domains will be aligned and the stronger the magnetic force. Once all the domains are aligned the material is said to have reached saturation and its magnetic properties will be at their maximum.
They cannot be improved with the application of any more magnetic force. With soft irons the domains align easily whereas more magnetic power is required with hard materials. However, with soft irons the domains will be scrambled again when the external magnetic force is removed, whereas in harder metals, a greater proportion is retained, making it a stronger magnet.
This is why soft iron is used for the core of coils, allowing what does demoted mean in clash of clans rapid build up and release of magnetism. Magnetic force The best way to describe a magnetic field is to imagine invisible lines of force parallel to each other entering the magnet at its south pole, travelling through it before exiting at the north pole, in a closed loop.
The magnetizing force of an electromagnet, which is in effect a magnet charger, is proportional to the number of turns of wire in its coil to the current flowing through this wire for 1 meter of coil; e.
The overall strength is known as the flux density of the magnetic forces and relates to the number of these flux lines in a magnet within a given area.
If the magnetizer will be used to charge modern rotating magnetos, which are best charged assembled, an allowance should be made for air gaps. An air gap can also mean a non-ferrous material like aluminium or other material used in the construction of the magnetos after the early horseshoe types. For two air gaps as small as 1 mm each, the strength of the electromagnet flux density might fall by a factor of five or more, so the flux density will need to be five times higher to compensate.
Having said all this, I must also repeat my comments earlier under magnetic domains that when charging a magnet there is a point when no matter what force is exerted on it, its strength will not increase once all the domains become saturated. Saturation occurs at around 1. Designing the charger There are three aspects to the design how to make a horseshoe magnet the magnet charger: the size of the core and frame, the length and thickness of the copper wire to be used as the windings, and the voltage to be used.
Before starting the design, a clear understanding is needed of the type of magneto to be charged. Lucas, a major high-tension magneto manufacturer here in the U.
Another design consideration is how the magneto will fit between the coils, either by using various pole pieces on the top of the cores or by moving the coils themselves. Core and frame In deciding on the surface area of the coils, the magnets on the low-tension magnetos available were measured, as the prime intention was to continue in the restoration of low-tension ignition engines. However, the construction of the charger was to be a what is the best zombie movie project, not to be repeated, so to give added flexibility it had to be made to a specification that made it capable of charging a wide range of magnetos.
Where there were two magnets joined and working together on a magneto, the combined measurement was taken. To get the best results in recharging a magnet the source needs to have between two and two and a half times the surface area of the magnet so the magnetizing force from the charger is concentrated in the magnets.
As can be seen from the table, the largest cross section was 2 square inches, giving rise to an optimum core area of 8 to 10 square inches. Therefore 3.
The core of a charger should be able to reach magnetic saturation as easily as possible, so the best material to achieve this is Swedish magnet iron, which is extremely pure. This is not readily available, so the next best option is to find a steel that has a very low carbon content, such as C which has a carbon content between 0.
The more carbon there is in the steel, the more magnetic force is needed to reach saturation, and some of this magnetism will be retained when the magnetizing force is removed. To get the best results the core needs to be as short as possible, but the design of an excessively short and fat core makes it difficult to fit a magneto between them so there has to be a compromise.
The arms of the cores on this charger would be made from two pieces of iron 6 inches long, which, after allowing for the insulation rings at each end and the platform at the top, left around 5 inches of the core for the actual winding of the copper wire.
Power source Calculations for this charger were based on using a volt battery, which is an easy source of power without the need to use a transformer to change mains voltage and a rectifier to smooth it out. If a higher voltage is used, the amperage increases proportionally, thus increasing the amp- turns, so if necessary two batteries could be joined in parallel to obtain 24 volts.
Another point to bear in mind when using batteries is that the voltage might drop to 10 volts when the battery is delivering peak current. Copper wire Copper wire is sold by weight, on different sized spools. The resistance of the wire is measured in ohms, putting a value on how easily an electrical charge will travel down the wire, which for winding wire is generally expressed in ohms per 1, feet.
With a thicker and low resistance wire, more charge will go down it, so the diameter of the wire chosen needs to be sufficient to allow the amperage necessary to obtain the desired level of magnetism. As the resistance varies according to the length of wire used, the resistance of a coil in relation to the number of ampere-turns also depends on the diameter of the core.
For a 1-inch diameter coil the length of wire for one turn of how to handle disruptive behavior in the workplace first layer is 3. Therefore, in calculating the ampere-turns of these different sized coils at 12 volts DC, a pattern emerges that the optimum wire thickness is less for the smaller diameter coil.
There is how to make scratch off valentine cards a point where the efficiency of the ampere-turns reduces rather than increases. The ampere-turns table at the top of this page sets out a summary of the calculations for one of the two cores of a charger, the wire being wound over a 5-inch length of the core.
This shows that doubling the number of turns does not necessarily mean a doubling of the ampere-turns, because of the resistance of the wire. In the case of the 3-inch core and the particular resistance of the 10 gauge wire used, it was found that the length of wire used increases proportionally to the turns so there is no change in the ampere-turns. It so happened that 4-kg spools of 10 gauge wire were available, each of which held feet.
This was convenient as one spool of wire could be used per coil and there would not have to be any measuring or counting of the number of turns. Wiring circuit Before going any further, an important decision is how to wire up the two coils and the battery, whether in series or parallel.
Wiring in series doubles the resistance of the coils, thereby reducing the flow of current or amps. In parallel, the total resistance is half the value of one coil. The resistance of the wire used in one coil is 0. This means that if the two coils were wired in series, the total resistance would be double, 0. Wiring the same two coils in parallel, the combined resistance is 0. This assumes a volt voltage from the battery.
If it reduces to 9, the ampere-turns reduce to 33, Heat When a current is passed through a copper wire, the wire starts to generate heat, the amount being related to the current in amperes and the resistance of the length of the wire. The shorter the length of wire the lower the how to capture video in android and the greater the heat generated. The resistance of the copper wire eventually selected was what are the properties of a table in html. As can be seen, the coil will quickly heat up, and it is therefore imperative that as soon as peak magnetism is achieved it is how to get kyogre and groudon in pokemon emerald off again or else there is the risk that it will overheat.
If thinner wire is used then the resistance reduces, and so will the heat, but this will also reduce the number of ampere-turns and the effectiveness of the charger. Final plans Having decided on the basic dimensions of the cores and wire to be used, the next step was to draw up plans to get a clear idea of how the charger would look and order the materials. Bringing some understanding in a nontechnical way as to how the simple battery and coil and the low-tension rotary magneto ignition systems how to be a house sitter. David Cave creates his own documentation through this internal and external examination of his Weidenhoff model magnet charger.
By Peter Rooke Jul 28, The basic concept of a magnet charger showing the alignment of the poles to the current flow. Webster AMM magneto with two tungsten magnets.
The roughness in the surface of the magnets can be seen. Low-Tension Ignition System Bringing some understanding in a nontechnical way as to how the simple battery and coil and the low-tension rotary magneto ignition systems work. Weidenhoff Model Magnet Charger David Cave creates his own documentation through this internal and external examination of his Weidenhoff model magnet charger.
Apr 24, · There are a few ways you can charge a horseshoe magnet to restore its strength. Get an electromagnetic charger. This type of charger is made of metal coils and an iron base. The metal coils produce a magnetic field that is able to transfer magnetic energy to the weak magnet. You can either purchase an electromagnetic charger or a kit from which you can assemble your own magnet charger. Jul 28, · Magnet steel Up to the s, horseshoe magnets were made from the toughest steel then available, tungsten steel. Since then, other strongly magnetic steels have been made, containing chromium and nickel up and until the s when compressed metal powders such as alnico and Alcomax were used. Dec 01, · Remove the top screw AND the thumbscrew. Pull the cover up toward the front where the stylus cradle is. Be careful, there is a copper spring (small flat piece about 1 inch by half an inch) on the arch of the magnet to keep it secured with the cover on. Carefully unsolder the coil’s wires from the cartridge connectors.
Be careful, there is a copper spring small flat piece about 1 inch by half an inch on the arch of the magnet to keep it secured with the cover on. Remove the magnet and both nuts then gently pull up the assembly. Keep the magnet in a steel tray or use a keeper; a small steel flat bar, across the magnet poles to keep its magnetization.
Careful with that coil! This is the needle cradle. I already replace the dried rubber dampers with silicone sleeves. I make my own by buying silicone rubber bands.
They are the right thickness. Otherwise, using silicone caulking and spreading a very thin layer on a mica or other non sticky material. Once fully cured, cut strips and use as dampers. This is the only place this sort of material can be used. Silicone is not the best damping material, but in this case we can use the self lubricating properties of the silicone to offer less friction to the cradle and offer some damping. The frequency response will be enhanced slightly in the highs.
NEVER use a rubber band here or a glob of silicone. We need the cradle to freely move without any free play. The freer the cradle, the better the frequency response. Too much free play and the cartridge will distort and destroy the records in no time.
Less friction on the cradle with proper damping from the centering damper on the back also means a better high frequency response. The main damper is rebuilt using good man made rubber very soft. I laminate two pieces for correct thickness and two side by side.
The cradle pole piece will sit right in between. Use contact cement or other pliable glue. If you can find a single piece of soft man made rubber natural rubber will dry and become hard faster then cut it to fit the assembly then cut a slice right in the middle lenghtwise almost all the way through.
Carefully reassemble the transducer. Fit the coil. The wires should come out the back of the stylus cradle opposite where the thumbscrew installs.
Install the second half and loose fit the brass screw both brass screw should be loose fit for later adjustment. Now, for the first adjustment. Both brass screws from the centering plate should be loose enough to allow both halves to move. Squeeze both halves until they barely touch the cradle seen on the left. There should be no pressure on the cradle but just enough to keep it from -wiggling- excessively.
In one word, no excessive play. Secure both nuts but not too thight for now as the cradle should be centered once the metal cover is reinstalled. Now, centering the pole piece is easy.
Hold the needle cradle with one end and center the pole piece in the transducer by moving the brass plate. Tighten both brass screws when done. Connect the amplifier wires to the back connector and rub a finger on the needle cradle to verify there is output. Put the metal cover on without the magnet if you wish and verify that the cradle is centerd.
If not, remove cover, loosen the both nuts, move slightly, resecure the nuts, put back the cover…. You get the idea…. Once the cradle is properly centered, put a drop of nail polish on the nuts. Secure the cover, install a new needle and test. It is difficult to explain how much the magnet should pull, but a healthy magnet should give a good pull and not be easily removed when put on a steel keeper or container. If the magnet is too weak, output will suffer.
There are outfits and even how-to for remagnetizing magnets which involves a high power electromagnet. Coils can be rewound, if you have patience and access to 40 gauge wire.
There are two types of horseshoe reproducers. Low 8 to 20ohms and high impedance. Not that it would matter much though. I found a way many years ago to restore the horseshoe magnets the easy way and permanently, adding even more output.
I was able to get a solid 3V with that trick. Maybe I should update this lesson. Low output may very well be caused by a weak magnet.
A healthy magnet should give a good firm pull when sat on a steel plate. Hard to describe what is right though. The pickup shown in the directions is the one for a Victor RE This pickup has an impedance of Ohms, and a DC resistance of about 85 ohms.
The original coil, shown in the pictures, was molded into a soft wax block, which did make it easier to handle, and to install in the pole pieces. If you can rewind the coil with a slightly smaller gage wire, you can add a few extra turns, and get more wallop from the pickup. I sent it to a friend in Baltimore, who has a real killer of a charger, and he charged it for me.
I was amazed at ow much this thing puts out now. For instance, what type of rubber can I use for the damper material? And what type of tubing should I use for the pivot? So, at an Antique Phonograph Society swap meet, I asked someone who gave me the following advice for the rubber:.
For the pivot, a small section of the white tubing used to rebuild Victrola reproducers works fine. I have a Victrola, so that will probably come in handy later. For the chunk of rubber that is used for the damper, I was advised to use rubber that has a softness of 40A on the Durometer scale.
Any rubber experts, feel free to comment and post links for more info. There are three scales to measure softness, and the rubber I bought was rated 70OO which skews slightly softer than 40A on the scale. It was under six bux in November of I chose it because it was cheap, the right thickness, and seemed to be resistant enough to air pollution, and of course vibration, which it will get plenty of when records are played.
My first test play sounded decent, with neither boomy bass or tinny treble, so I think I got the rubber combination pretty dang close. I was lucky: My coil was good and the magnet was strong enough for good volume. It was plenty loud! I had to keep the volume fairly low to keep the speaker from shooting through the wall and hitting my neighbors. So, yeah, it was strong enough! I hope this additional information helps the next person searching for info on rebuilding these phonos!
Silicone rubber bands… I found some great ones. I use cooking bands for the smaller strips but for the block piece I use the silicone bracelets they have for cancer awareness and misc.
They can all be bought online cheap. Pull the cover up toward the front where the stylus cradle is. Seen from the back, the cradle damper and centering adjustment. That rubber piece must be replaced. Install the needle cradle. Note where the wires come out.
Install the pole pice in the centering damper. This is what it should look like from the back. You get the idea… Once the cradle is properly centered, put a drop of nail polish on the nuts.
Hard to tell. I suspect you do not have a schematic available? Wiring as you [describe] it sounds OK. Average should be around VPP. So, at an Antique Phonograph Society swap meet, I asked someone who gave me the following advice for the rubber: For the pivot, a small section of the white tubing used to rebuild Victrola reproducers works fine.
OldRestorer Wrote: Silicone rubber bands… I found some great ones.