Xcom Enemy Unknown Patch 3. The online magnet charger article is from a very interesting book. Believe it or not the whole book can be downloaded for free from. Check the left side of the web page to choose your format. Its available as a PDF for your PC or other formats for even a Kindle.

---------- Post added at 12:04 PM ---------- Previous post was at 11:43 AM ---------- The link I posted earlier has a link that takes you to Google Books. You could go directly here ---------- Post added at 12:13 PM ---------- Previous post was at 12:04 PM ---------- The encyclopedia linked here is the 1920 version. The magnet charger plans are not in it anymore. They switched to charging $1 for the plans sometime between 1918 and 1920. The online magnet charger article is from a very interesting book. Believe it or not the whole book can be downloaded for free from. Check the left side of the web page to choose your format.

Electrical parts numbers Black Shadow/Rapide Magneto KVF42134 (KVF GM1) Contact set 470877 Contact set 54440890 (late style) Contact assembly 54440863 (late style. AIRCRAFT SPRUCE CATALOG PDF DOWNLOAD: To view the files you'll need the Adobe Acrobat reader. If you don't have the Adobe reader, you can download it.

Its available as a PDF for your PC or other formats for even a Kindle. ---------- Post added at 12:04 PM ---------- Previous post was at 11:43 AM ---------- The link I posted earlier has a link that takes you to Google Books. You could go directly here ---------- Post added at 12:13 PM ---------- Previous post was at 12:04 PM ---------- The encyclopedia linked here is the 1920 version. The magnet charger plans are not in it anymore. They switched to charging $1 for the plans sometime between 1918 and 1920. I am looking for a plan that uses a 12 volt battery and I found a play by John Rex but that one sounds like overkill.

Tim Your first decision is to identify the type of magnetos you want to re-charge, HT or LT. How wide will the magnet bars be. What will your power source be. You can then design your charger to meet these criteria. If you want to use 12 volts and really zap a large magneto then the Rex size will be more appropriate than the Gingery. For LT magnetos the common view is that you will need to achieve 20,000 amp turns (turns of wire around the cores x amps drawn by the copper wire). I set out there the theory behind the charger I made.

Tim Your first decision is to identify the type of magnetos you want to re-charge, HT or LT. How wide will the magnet bars be.

What will your power source be. You can then design your charger to meet these criteria. If you want to use 12 volts and really zap a large magneto then the Rex size will be more appropriate than the Gingery. For LT magnetos the common view is that you will need to achieve 20,000 amp turns (turns of wire around the cores x amps drawn by the copper wire). I set out there the theory behind the charger I made. Peter What is the difference between HT or LT magnetos ---------- Post added at 06:22 PM ---------- Previous post was at 05:53 PM. What is the difference between HT or LT magnetos ---------- Post added at 06:22 PM ---------- Previous post was at 05:53 PM ---------- how much does the rex charger weigh thanks I wasn't aware that there was a difference between HT (high tension) and LT (low tension) magnetos when it came to charging the magnets.

I've charged both on my charger successfully with the same methods. The Rex charger is so big it needs a two-wheel dolly to move it around. Personally, I think the Rex charger is overkill. My Gingery charger has brought back to life every magneto I have charged on it, and that's all that matters to me. I read somewhere that there is only a certain amount of magnetic saturation that can be reached when charging magneto magnets and any charger that is built big enough to go beyond that point is overkill and there are no benefits to be gained.

According to Gingery, his design provides all the saturation needed to charge ordinary magneto magnets. Why drive a nail with a 20lb sledge hammer when a 20oz hammer will do the same job? I wasn't aware that there was a difference between HT (high tension) and LT (low tension) magnetos when it came to charging the magnets. I've charged both on my charger successfully with the same methods.

The Rex charger is so big it needs a two-wheel dolly to move it around. Personally, I think the Rex charger is overkill. My Gingery charger has brought back to life every magneto I have charged on it, and that's all that matters to me.

I read somewhere that there is only a certain amount of magnetic saturation that can be reached when charging magneto magnets and any charger that is built big enough to go beyond that point is overkill and there are no benefits to be gained. According to Gingery, his design provides all the saturation needed to charge ordinary magneto magnets. Why drive a nail with a 20lb sledge hammer when a 20oz hammer will do the same job?

Is there plans for the gingery to use 12 volt battery? You want the magneto magnets to reach magnetic saturation before the coils on the charger reach saturation.The only way to do that is large coils with a lot of core mass. The Rex charger will charge any mag you can throw at it. As an experiment charged a WICO EK on an Allen charger which I think Gingery based his charger on.

Using a force gauge to pull the armature it tripped at 30lbs. After charging on the Rex it took 68lbs. Most of the small chargers will charge a mag but not to its full potential. [QUOTE What is the difference between HT or LT magnetos] Talking about HT or LT magnetos is a general view to differentiate them, as to whether the magnets are made of different materials of increasing hardness. The old LT horseshoe magnets were made of Tungsten Steel, then steels containing chromium and nickel and in the 1930's compressed metal powders. The harder the magnet the more amp turns are needed to get it to reach its full magnetic potential.

60,000 amp turns are recommended to fully charge a 1930's magneto, particularly if there is what is known as an air gap, (air or non ferrous material) between the charger coils and the magnets. As already mentioned here - are you looking for a charger that will work as well as a commercial charger to restore a magnet to as near its original state as possible or just want to give it a 'tickle'. [QUOTE What is the difference between HT or LT magnetos] Talking about HT or LT magnetos is a general view to differentiate them, as to whether the magnets are made of different materials of increasing hardness. The old LT horseshoe magnets were made of Tungsten Steel, then steels containing chromium and nickel and in the 1930's compressed metal powders. The harder the magnet the more amp turns are needed to get it to reach its full magnetic potential. 60,000 amp turns are recommended to fully charge a 1930's magneto, particularly if there is what is known as an air gap, (air or non ferrous material) between the charger coils and the magnets. As already mentioned here - are you looking for a charger that will work as well as a commercial charger to restore a magnet to as near its original state as possible or just want to give it a 'tickle'.

Peter I am not sure what 60,000 Amp turns mean. ---------- Post added at 08:29 AM ---------- Previous post was at 07:34 AM.

Guys -- I don't have an electrical engineering background and I don't know where else to look on the 'net so I'm hoping that I can get a collective answer here: Briefly, I'm working on building a powerful electro-magnet that I'll be using to re-magnetize vintage motorcycle magnetos after they've been rebuilt. I'm modeling mine after the physicist Charles Falco's who's been gracious enough to share his plans with me. The big stumbling block is where can I source the soft iron needed for my core? I'm looking for a round of 3.5' in diameter up to 33' in length. I'll be cutting and then machining it in three sections. In days gone by it was known as 'Swedish Steel' (because the Swede's were arguably the best at making the stuff back in the 1950's) or sometimes as 'Armco' steel (for American Rolling Mill Company who were also makers). This isn't your basic round of mild steel.

Again, it's soft iron that is 99.8%+ pure iron. Is anyone familiar with this or know where it can be obtained stateside? I really need this because, as per the attached picture with notes, I'm shooting for an electro-magnet that will provide me with a core winding of 75,000 ampere/turns. It'll be drawing somewhere around 18 amps off at 220 volts. I can't use mild steel because then I won't be able to achieve the level of magnetic saturation needed. I asked Charles where he sourced his and as he built his over ten years ago he's not sure where his core material came from.

I also asked him if I could bundle smaller rounds or even soft wire together to get the needed overall diameter but he was doubtful as to it's effectiveness and said any changes on my part from his plans means I'm on my own. I'll finish for now by writing that I'm going with such a strong electro-magnet because the last generation of 1950s-era motorcycle magnetos had alloy magnets that were about 26 times stronger than the old tungsten steel based magnetos of the 1930s. Does anyone have any thoughts on this? Thanks -- Chris.

I had a good relationship with a local magneto repair shop and I would re-magnetize magnets from my own magnetos, speakers and polar relays. The magnetizer was rated at 6 volts 300 amps. Commercially made and quite old. Two 6 volt heavy-duty batteries were wired in parallel, estimated 400+ amp/hrs available.

Control was simple, old truck floor stater button wired in series with the magnetizer. Place work and pole pieces on surface poles, block of wood so pole pieces don't jump together. Keep fingers away. Press button, smack magnet with hammer, release button, done. The core of the magnetizer was not laminated as the flux was not changing. Late 80s/early 90s I had occasion to work with a machine that was used to magnetize the flywheel magnets for 2 stroke engines.

The machine dated to the late 70s, and I had to do some repairs on it to get it working. Then, we used it to magnetize several thousand ceramic magnets for some 'jet-ski' engines. This machine had 2 rack shelves of large electrolytic caps arranged in series and parallel (with balancing resistors). I am not sure anymore how many milli-farads this was in total.

Seemed like a lot at the time. The caps were charged with a SCR bridge connected to the secondary of a step up transformer. The machine ran off ordinary 120VAC and not a lot of current. There was a control board using TTL logic and some analog stuff that controlled the SCR bridge for charge rate and regulation of the final voltage. The charging voltage was loosely regulated and could be set with a knob on the front panel. I recall the max was 600VDC.

A button on the front panel interfaced with the logic board, and when pressed (provided the interlocks were in place), dumped the charged capacitor bank via a big stud SCR on a heatsink to the coil that was wound on the fixture where the magnet was. The front panel had a connector for 4 gauge cables.

Cables ran to the fixture along with interlock signals so you could not discharge the cap bank unless the fixture was 'closed'. Very important. Per the manual, this machine was capable (depending on the circuit impedance), of something like 10,000A peak. The magnets we needed to do where about 1-1/2' wide and 3' long and arc shaped. I think the flywheel they were to go in took 6 of them. I know we had to magnetize 1/2 of the batch 1 direction and the other 1/2 the other direction N vs S.

I came up with a simple fixture for this and the guys in the shop made it up. We got a sheet of silicon steel someplace and made a lamination stack the height of the magnet. There must have been at least 20-30 sheets stacked, maybe more.

The core was designed in 2 halves and 1 was fixed in place. The other could slide on the big sheet of phenolic we used as a base. The magnet fit in the gap on 1 leg and the other would butt tight when the sliding half of the core was shoved together. There was a limit switch on the sliding half that closed when it was closed, so that provided the interlock. The coil was wound on a pc of plastic that fit over the lamination. I think it was something on the order of 30 turns of 3/16' dia copper tubing. I was worried this was going to get hot, so I used copper tubing and compression fittings on the ends into aluminum blocks where I had both electrical and water connected.

The 4 gauge cables connected to the 2 aluminum blocks with bolts and I had hoses to run water through the tubing. Turned out I wouldn't have needed to bother with the coolant since the duty cycle of the pulse was pretty low and the winding barely got warm.

The recharging time and time it took to pull out the last magnet and get another one in was slow enough that things didn't get that hot. It was very important to have clean and tight bolted connections on this. Also, the cables from the machine panel to the fixture needed to secured from moving. When you have 1000s of amps current, you find out first hand the electromagnetic fields around the wires interact with each other and the earth and any nearby metal. Your cables will jump.

The reason for the interlock on the fixture was the magnetic field would pull the fixture together tightly and you would not want a finger stuck in the gap when it did so. When discharged, there was a distinct 'thump' sound. This machine came with a gauss meter, and how you used it was to start off with some low charging voltage. Pulse the magnet, then pull it out and measure the field. Then increase the voltage, remeasure, etc until it would not get a increase in strength. Any excess voltage =>higher peak current was wasted as the goal was to saturate the magnet.

That was how the machine was set for the run. Also, the meter could be used to check things were going OK from time to time.

That was a fun machine to work on. Good memories.

5000 turns of #14 seems like the hard way to do things. Also, what is used for an ON/OFF switch in the 'soft iron' approach? I worked on re-building a magnetizer for lawn-mower engine magnetos back in the 70s. It had a capacitor bank and a thryratron/ignitron combination to do the ON/OFF switching. Since we weren't concerned with a fast duty cycle, the capacitor bank charged from a small DC supply via a series resistor. When the caps hit the desired voltage, the ignitron could be fired to dump the charge into a set of magnets with fewer turns of wire.

I believe special caps were used to handle the high pulse currents. The circuit shown has only 90A of magnetizing current, so needs a lot more turns for the same field strength. With caps, you might achieve thousands of amps of peak current and correspondingly, less turns. You don't need a continuous current to magnetize. Unless I had hundreds of magnets to restore, I wouldn't go to the expense and effort of building a magnetizer. Did you contact AK Steel?

They are still in business. If available, they should be able to direct you to a dealer. Been a long time since my transformer studies, but I can't imagine why you could not laminate the core. I would think the eddie currents would be a killer on a hunk of iron that size.

Do these old motorcycle magnets look like a horseshoe as in the picture? And this Charles guy sounds a little off. If building a traditional magnetizer, I'm wondering if I could get away with salvaging the laminated core from a VERY large power transformer? The old magnetos had horseshoe-shaped magnets until the early 30s.

They became separate pieces usually cast into the aluminum housings after that and were magnetized with specially-shaped pole pieces before leaving the factory. I don't know Mr.Falco personally other than a sporadic email exchange, the Wikipedia entry about him and his exhaustive posts on the BritBike forum and AMCA articles. His personal expertise seems to be in optics. I had a good relationship with a local magneto repair shop and I would re-magnetize magnets from my own magnetos, speakers and polar relays.

The magnetizer was rated at 6 volts 300 amps. Commercially made and quite old.

Two 6 volt heavy-duty batteries were wired in parallel, estimated 400+ amp/hrs available. Control was simple, old truck floor stater button wired in series with the magnetizer. Place work and pole pieces on surface poles, block of wood so pole pieces don't jump together. Keep fingers away. Press button, smack magnet with hammer, release button, done. The core of the magnetizer was not laminated as the flux was not changing. GL I've seen those and I have plans for one, but they're only good for re-magnetizing the magnetos of old hit/ miss engines as usually seen at old farm machinery shows or those off the earliest motorcycles.

Generally good for 20,000 amp/ turn and not nearly enough to achieve the level of saturation needed for a later alloy type magneto requiring a ~75,000 amp/turn magnetizer. Late 80s/early 90s I had occasion to work with a machine that was used to magnetize the flywheel magnets for 2 stroke engines. The machine dated to the late 70s, and I had to do some repairs on it to get it working. Then, we used it to magnetize several thousand ceramic magnets for some 'jet-ski' engines.

This machine had 2 rack shelves of large electrolytic caps arranged in series and parallel (with balancing resistors). I am not sure anymore how many milli-farads this was in total.

Seemed like a lot at the time. The caps were charged with a SCR bridge connected to the secondary of a step up transformer. The machine ran off ordinary 120VAC and not a lot of current. There was a control board using TTL logic and some analog stuff that controlled the SCR bridge for charge rate and regulation of the final voltage.

The charging voltage was loosely regulated and could be set with a knob on the front panel. I recall the max was 600VDC. A button on the front panel interfaced with the logic board, and when pressed (provided the interlocks were in place), dumped the charged capacitor bank via a big stud SCR on a heatsink to the coil that was wound on the fixture where the magnet was. The front panel had a connector for 4 gauge cables. Cables ran to the fixture along with interlock signals so you could not discharge the cap bank unless the fixture was 'closed'. Very important. Per the manual, this machine was capable (depending on the circuit impedance), of something like 10,000A peak.

The magnets we needed to do where about 1-1/2' wide and 3' long and arc shaped. I think the flywheel they were to go in took 6 of them. I know we had to magnetize 1/2 of the batch 1 direction and the other 1/2 the other direction N vs S.

I came up with a simple fixture for this and the guys in the shop made it up. We got a sheet of silicon steel someplace and made a lamination stack the height of the magnet.

There must have been at least 20-30 sheets stacked, maybe more. The core was designed in 2 halves and 1 was fixed in place. The other could slide on the big sheet of phenolic we used as a base. The magnet fit in the gap on 1 leg and the other would butt tight when the sliding half of the core was shoved together. There was a limit switch on the sliding half that closed when it was closed, so that provided the interlock. The coil was wound on a pc of plastic that fit over the lamination.

I think it was something on the order of 30 turns of 3/16' dia copper tubing. I was worried this was going to get hot, so I used copper tubing and compression fittings on the ends into aluminum blocks where I had both electrical and water connected.

The 4 gauge cables connected to the 2 aluminum blocks with bolts and I had hoses to run water through the tubing. Turned out I wouldn't have needed to bother with the coolant since the duty cycle of the pulse was pretty low and the winding barely got warm. The recharging time and time it took to pull out the last magnet and get another one in was slow enough that things didn't get that hot. It was very important to have clean and tight bolted connections on this.

Also, the cables from the machine panel to the fixture needed to secured from moving. When you have 1000s of amps current, you find out first hand the electromagnetic fields around the wires interact with each other and the earth and any nearby metal. Your cables will jump.

The reason for the interlock on the fixture was the magnetic field would pull the fixture together tightly and you would not want a finger stuck in the gap when it did so. When discharged, there was a distinct 'thump' sound. This machine came with a gauss meter, and how you used it was to start off with some low charging voltage. Pulse the magnet, then pull it out and measure the field. Then increase the voltage, remeasure, etc until it would not get a increase in strength.

Any excess voltage =>higher peak current was wasted as the goal was to saturate the magnet. That was how the machine was set for the run. Also, the meter could be used to check things were going OK from time to time. That was a fun machine to work on. Good memories.

Sounds like something along the lines of a surplus loudspeaker magnetizer currently being advertised on Ebay the last I checked. Unfortunately I'm limited to residential 220 single-phase at best. 5000 turns of #14 seems like the hard way to do things.

Also, what is used for an ON/OFF switch in the 'soft iron' approach? I worked on re-building a magnetizer for lawn-mower engine magnetos back in the 70s. It had a capacitor bank and a thryratron/ignitron combination to do the ON/OFF switching. Since we weren't concerned with a fast duty cycle, the capacitor bank charged from a small DC supply via a series resistor. When the caps hit the desired voltage, the ignitron could be fired to dump the charge into a set of magnets with fewer turns of wire. I believe special caps were used to handle the high pulse currents.

The circuit shown has only 90A of magnetizing current, so needs a lot more turns for the same field strength. With caps, you might achieve thousands of amps of peak current and correspondingly, less turns. You don't need a continuous current to magnetize.

Unless I had hundreds of magnets to restore, I wouldn't go to the expense and effort of building a magnetizer. Rich Rich, thanks for your link to this outfit in Colorado. The one they sell is only rated for 24,000 amps/ turn but maybe they can provide me with plans for one of a higher capacity.

And I'd rather use one with a bank of capacitors in comparison to a traditional magnetizer which will require almost 100 lbs of iron and some 60 lbs of copper -- thus saving on the expense. A true, working knowledge of magnetos seems to have devolved into something of a black art with only about a dozen professional rebuilders in Europe and fewer still here in the U.S. None that I know of here on the West Coast -- unless it's for aircraft.

And the last outfit I used near San Francisco lacked the properly shaped pole pieces neccessary to magnetize mine and was clueless about set-up. Soft iron as far as I know hasn't been available for decades. The only iron with less carbon content than the various grades of mild steel would be wrought iron (not to be confused with what is commonly called ornamental wrought iron now, which is mild steel). On the forum at woodenboat. Download Matlab Toolbox Symbolic Logic. com there are occasional references to wrought iron, in demand by boat builders or restorers because it resists rusting better than mild steel. In one of those discussions I found by searching, the only present-day supplier of wrought iron was in England and 1' diameter rods were specifically mentioned. There is a long-running thread on that forum by a volunteer at Mystic Seaport working on the restoration of the 1841 whaling ship Charles W.

In need of genuine wrought iron for the chains that anchor the mast stays ('chains' being solid iron devices mounted outside the hull, not what we normally think of as chain), they obtained some from (I recall) the dismantled lion cages at the Atlanta Zoo. The material simply isn't made any more. Even when it was, it was apt to contain significant amounts of slag. I would recommend using the softest mild steel available.

There are, according to a handbook I have, several grades with varying magnetic properties. Also: Google 'Meehanite magnetic properties' there is a pdf with a notated hysteresis curve available.

For other cast iron slabs suitable for machining there is McMaster Carr: Most iron grades can be accessed by doing a spark test. I see there are sprigs for magnetic properties. IMHO: A trip to a local industrial scrap yard could be a very rewarding adventure. All sorts of materials wind up there and could prove to be the foundation of your project. Bring your battery powered Dremel. And one pays only a few pennies over the actual scrap price.