Please have a look at these photos and maybe you could suggest a voltage to use on this Puppy!

Perhaps Ron the Coilman could suggest what power to use on this charger. I've tried a small 12v garden tractor battery which works but not too impressive. I would guess I need something that can put out the amps ie a 4 D. Would 36v be more aproppriate?
Would one lay the magnet flat or stand on end to charge it?
When using the meter does one lay the meter contact parrel or 90 degress to the meter contact?
What would be considered a good reading on the meter. One gets different readings depending how the magnet is held against the meter contact!
When I put the meter on the magnets mounted on the flywheel I see 24 to 26 units.
A friend found this magnet charger in a pile of T parts he picked up a few years ago, but has never used it. Since I'm rebuilding a 13 engine I thought I might try it out!

You have some neat stuff! I'd place the magnet straight on to magnetizer and the meter. Although I do not think it makes much difference. What is important is that you have a complete magnetic circuit. Meaning that the magnetic flux has a closed loop to pass through. I have no idea what the units are on the meter. If it were mine, I'd use the meter as a comparision unit. You could compare magnets as you magnetize them. Are the meter terminals marked for north and south? Does the meter read backwards if the magnet is turned around? What voltage to use? I would guess that since this is an old unit probably some multiple of 6 volts. The more voltage you apply to the electro magnets the hotter (temperature) the coils will get and you may damage them. I built my own charger and used a 12 volt battery. I found that if you pulse the current (connect and disconnect the battery) the magnets seemed to have a better charge. The rule of thumb that I used was that if the magnet could pickup 3 lbs after charging it was good. You should check each magnet for cracks. An easy way is ring it like a tuning fork, but don't hit them to hit or they will break. If they ring there is no cracks, but look closely also. Hope this helps.

Mike
Yes The meter reads from 0 to 50 ( whatevers). I seem to be able to charge a magnet as far as 25 Units. It will hold a cast iron piston and wrist pin, ( a little over 2 lbs). Yes one terminal is marked + but nothing else. I've had as much success charging a magnet using the 10 guage house wire wrapped around the magnet 8 times each side using the same small battery. No the meter does not read in reverse if you change the north or south side of the magnet on the meter.
Oh yes I'm aware of the crack issue and will be checking each one. Thanks for the hint.
I've read through many threads on this topic , but I have never seen a charger quite like this one. I wonder if any other members have seen these?
Wilf

Go to http://www.old-engine.com/magsum.htm for more information. There is too much to print here. That info says use 120 VAC and rectify it.

After looking a little closer to the meter picture, is there only one spot for the magnet to touch or two?

Mike
Just one!
Wilf

Mike
Thanks for the link. I wonder if this charger was ever used for T magnets?
Wilf

Wilf
There is no doubt in my mind that your Weidenhoff Company magnet recharger is a purpose built unit for recharging Model T magneto magnets. Weidenhoff was a large automobile test equipment manufacturer and also made hand cranked coil testers and other electrical testing apparatus. The Weidenhoff Magnetometer is a relative strength testing device to check recharged magnets.
I have a Bosch Model T magnet recharger unit similar to yours. In the photos you can see how the mandrels are specifically shaped to accept a Model T magnet. I use two 12 volt automobile batteries in series to power it and the result is a recharged magnet will easily lift a Cast iron Model T piston/pin which is 2 3/4 pounds.

Ron the Coilman

Thanks Ron
That's what I wanted to know.

Cheers Wilf

Ron, I've looked at your charger before and have a question about the stand that the V end of the magnet sets on. Is that a critical part of the charger? In other words, do the magnets charge better because they are touching an iron piece at the end opposite the ends that are having the "magnetic flux" applied to them?

Stan
No. The stand that supports the "vee" of the Model T magnet is non magnetic. A wooden post with a brass top where the magnet rests.
Ron the Coilman

I have a charger much like Ron's also and will offer another ability it has. A couple of weeks ago I recharged a magnet on a Fairbanks Morse magneto. This in one of the round magnets like found on many airplane mags (Slick, Bendix, Case, Eismann, etc.). I split a piece of exhaust pipe the same diameter as the magnet and welded the tubing pieces to a couple of flat pieces of metal on one end. I then clamped each half to the magnet charger and put the rotor in and zapped it. When doing these types of magnets (any type really) you should install a keeper across them to keep them from losing strength. I used another piece of exhaust tube cutting one slit in it to slip over the charged magnet rotor.

If you need a keeper on a Model T magnet to keep it stong when it's out of the car,what the heck keeps it from getting weak in the car? 15 million were made that way.

Jack

How were the other 70,000 plus made???

Mike Hager

Distributers,no magnets and water pumps!

Good answer Jack!!! Have a great Day!!!

Mike

Mike,I couldn't resist. (G)

When installed they are in close enough proximity to one another and to the flywheel that is doesn't matter. We all know magnets (even installed on the flywheel can become weak over time). In an uninstalled state that happens even quicker.

I have rebuilt a number of airplane mags which are basically the same as antique tractors and was taught years ago that when the rotor is removed it should always have a keeper across it. Bendix was very clear on this when handling their mags. I tend to follow the maintenance advice of the manufacture.

The following if from an engineering page I found on the net: " A magnet may also become weakened from loss of flux. Thus when storing magnets, one should always try to avoid excess leakage of magnetic flux. A horseshoe magnet should always be stored with a keeper, a soft iron bar used to join the magnetic poles. By using the keeper while the magnet is being stored, the magnetic flux will continuously circulate through the magnet and not leak off into space."

The magnets used in the T are basically horseshoe magnets.

Correct me if I'm wrong, but the original magnetometer's only went to 30 units that they display in the service manual. So, your magnet showing ~25 units is pretty strong. I would try picking up a few things with the magnet to test it's strength...

Also, there looks like there is a lip on the metal mounting surface of your meter. I imagine that the magnet gets placed between that lip and the tab that hangs down.

I think the reason that the installed magnets on the flywheel don't lose their strength very fast is because they are installed with the north poles side by side and the south poles side by side. That way they are opposing each other and forcing the flux back in, not allowing it to "leak off into space".

BTW, when I store spare magnets I glom 2 magnets together, north to south, south to north. This works as good as a keeper.
In fact, I was looking at some spare magnets last night, stored that way, and after about a year they still easily pick up a 3 pound weight.

Speaking of weights, when I was an apprentice, the older fellow would tell the newbie to go and see so and so at the other end of the building and get the "big weight". Of course he got the big "wait".

I think the reason that the magnets are installed north to north and south to south is so when the magnets are over the pole pieces of the coil ring, the flux from the combined north poles travel through the coil pole piece through the iron of the ring, back out the south pole piece and return to the combined south magnets. Otherwise the magnetic flux would not travel through the coils and induce a voltage. I would think that half the time the engine would stop where the magnets are either directly or near the pole pieces, completeing the magnetic circuit, the other half the time the engine could stop where the magnets are in between the pole pieces. So some of the times installed magnets have a keeper and some times they don't. I always use a keeper on unused magnets and care should be taken so that the magnets are not bumped or dropped. A shape shock will also affect the magnetism.