I have looked over past posts and am still confused about the winding of magnet chargers. Some say they should be wound the same direction other say opposite. I wound these with 12 gauge solid core ... one wound clockwise the other wound counter clockwise. Is this correct?
Probably, but use a compass to confirm that one is a north pole and the other a south pole. If they are both the same pole in the configuration you have, hopefully there is enough slack in the wires to just flip one around (no need to rewind) so that one will be north and the other south at the ends where you plan to put the magnet.
You know I looked at this before and missed a couple things.
One mistake is using solid core wire. It won't carry as much current as stranded wire, so the charge will not be as effective.
Like Mark says hook up the power briefly with a compass at the end of each coil to verify it has reverse polarity on each. I think one or the other has to be inverted as shown in your photo, the wire coming off the end of the black side should be at the lower end of the right side. The compass will not lie.
Just slide the coils off, hook each one to a D battery, and use a compass to see what the polarity at ends of the coil are and mark it. Also mark which lead was positive and which one was negative when you hooked it up to the battery. Do the same with the other coil. Then slide the coils back on, positive-to-negative where you make your connection in between.
Remember that charging a magnet requires you to use the OPPOSITE pole. For instance, if you need to charge the south pole of a magnet, you'll need to use the north pole of your coil.
When you charge it, stick a hefty piece of metal in between the poles of the magnet. That will complete the magnetic Flux and give you a better charge.
Ha ... and here I thought it was actually suggested to use solid core wire! What a pain. These were a struggle to wind. These won't slide any further down so I can't connect a keeper between the ends. Guess I have to go back to the drawing board and rewire with stranded wire. I have a spool of stranded 12 gauge. Was going to us a single 12 volt battery with this set up.
You can charge right to left or left to right by switching which side takes the positive on the battery. Heat is the main issue so some sort of switch using just a bump flashing on a good battery by Kens post on magnets thread its over 300 amps.
Weight lifting will be much higher by pulling from a fixed plate not by dead lifting. A slight grind at a right angle to the magnet helps to keep it upright and better connection of the metal flux across the ends while charging. Its amps times the amount of wire turns your after.
People really do grind the ends just to charge their magnets? By bump flashing you mean striking one end of the cable to a contact rather than using say a house lighting switch? Should I rewire these with 12 gauge stranded then?
Never heard of stranded wire carrying more amps then solid wire of the same rating. Late house wire is rated for higher temperature then early. I would like to get a roll of oven wire because of its diameter would allow more wire turns.
Another prime example of gross misinformation propagated by the same poster that yet again misleads unsuspecting readers in thinking total BULLSH!T is gospel fact.
"One mistake is using solid core wire. It won't carry as much current as stranded wire, so the charge will not be as effective." TOTAL BULLSH!T
Solid wire with the same AWG has the same resistivity and DC current carrying capacity as stranded wire. Solid wire also costs less and has a smaller diameter than the same AWG stranded wire which makes for a cheaper, more compact, re-charging coil. Neatly wound Mark, I suggest you give it a try and test the results.
PLEASE do at least some basic research before making "factual" assertions that could mislead others into doing needless and costly re-work.
Here are a couple of references regarding solid vs stranded wire. Google is your friend.
Mark, I use an old vintage floor switch its spring loaded so it pops back when hit. It also puts any spark inside so battery gas has been not a problem. Four hits is about as much heat the coil can take without over heating 12 wire rated for 20 amps with over 300 amps. The odd thing I do not understand is the coil will pull to the magnet ends then spring back when the switch is off. As far as grinding the ends it allows more weight to be lifted because of more lifting area of a flat end. I could post a picture of one magnet charged several years past dead lifting an exact four pound paint scale weight with just enough grind so it sets upright switching that to pulling from a fixed plate would probably lift closer to ten pounds.
So really the only reason for grinding the game ends is to test the magnet once charged? What I hear people saying about charging magnets is that they are generally stronger than the original specs. So I'm thinking I don't need to take the time to grind the ends ... right?
You don't need to take the time to grind the ends at all. I think it's silly myself. All it does is allow a better surface with which to put something flat against to see how much weight the magnet can lift.
Yes, you can simply strike the leads against a car battery to achieve the desired effect. No switch is needed! Be careful, however. It throws some sparks and can chew up your battery terminals a bit. You'd need to use a heavy-gauge momentary switch. Remember, time here isn't important. It only takes a fraction of a second to charge a magnet!
A word of warning: If you're using a compass, keep it FAR AWAY when you're charging magnets. I now have one that points south instead of North
I like to use heavier gauge wire, such as 10 gauge. 20 turns or so per coil is all you need.
Also, keep in mind the basic theory of magnet charging. Iron can only be magnetized so much. Trying to put more magnetism into it than it can handle is called saturation, and this is exactly what the magnets need to be charged. The beauty behind using coils wrapped around the magnet ends is that an open coil with no iron in it (just air) can generate an almost infinite magnetic field (air cannot be saturated; it's not magnetic). That means that putting a coil with a few turns of heavy gauge wire on a Model T magnet with loads of current can easily drive it into saturation.
The other alternative is to build a magnet charger which requires a lot of iron to drive the T magnet into saturation without the iron in the charger itself getting saturated.
To answer your specific question "yes" but other considerations apply.
I asked you to call me for a complete explanation.
"These won't slide any further down so I can't connect a keeper between the ends."
A keeper doesn't have to be flat, bend down the ends of a piece of metal for a keeper so that the ends go down into the coils to contact the magnet.
I use a a 12 volt solenoid to switch the power to the recharging coils.
Mark, use a plain bar or round piece of any stock to straighten the coils into one continuous, but separated coil.
The turns on both coils should match, as if it was just one continuous coil.
Then they can be inserted back in the original fixture.
That piece also has to be soft iron for maximum effectiveness.
how to identify soft iron is not so easy to explain.
Thanks Ron, Ken and James--- Ron has the advantage of many wire turns so it takes far less amps to saturate a magnet. Ken is an electrician with tools to measure amps while charging---I don't. James is far more savvy with magnets then I am.
The only way I can test is by weight lifting.
What was found is one magnet might test better then another---guess that is soft iron. by weight testing with dead weight the scale of weight is much smaller then by pulling from a fixed plate that's is why I like to do a slight grind on the ends at a right angle to the magnet otherwise the magnet will not stand upright for testing on my test plate that has to have the magnet centered under the wheel lifting the nylon string attached to it. Just by laying a block of wood on the test platform dead weight can be checked----but its not as accurate.
I bought this little magnet strength measuring device to help determine the Gauss required to lift a 2 pound weight.
There were so many other variables that I did determine I could not establish a number.
What I did determine was that 2 pound weight lift test only provided the minimum magnet strength required to produce a working Magneto, if the space between the Magnet Poles and Coil Pickup Poles was around .025 to .030 and remained constant all around the flywheel.
Charging a magnet to pick up a 5 pound weight is not difficult, but what determines whether it will or not is the surface contact area between the magnet ends and the weight. Most Model T pistons had a top surface rough enough that not much more that 4 pounds could be lifted from the top, like these photos illustrate. Magnet test 2 would lift more weight, as the magnet end had more surface contact.