Another hobby of mine is hit and miss engines. In those circles, it is considered a big no-no to take a magneto magnet off of a magnet charger without sliding it onto a keeper then sliding it off the keeper into the magneto. Supposedly, if you don't do this, the magnets will loose half of their magnetism instantaneously! Then I get into the Model T world and find that you can take your magnets off the flywheel, put them in a box, send them off to be recharged, have them sent back to you and bolt them back on the flywheel with absolutely no mention of the word "Keeper." What's going on here? Is the magnet keeper deal an old wives tale? Are Model T magnets made of a different material that holds its magnetism better? What gives?
Thanks for your post, Hal. I'm also into flywheel engines and have been wondering the same thing.
Keepers are recommended and sent back on the charged magnets by at least some vendors.
I believe it's considered a "keeper" to ship and store magnets arranged in radial the pattern, similar to their positions when installed, with each magnet in contact with its neighbor and with the poles arranged N-S-N-S-N.... The brief time that it takes to transfer them to and install them on the flywheel is apperently of no consequence.
There is something to the Magnet keeper/saver thing. The magnetic bases for dial indicators have them for an example. My Hercules 2 1/2 HP engine with a Wico mag say's not to let the engine sit in a position to where the mag is kept open. The iron magnets are more likely to "Run Down" over time than the more modern ceramic magnets. I think the magnet saver serves to keep the flux or field complete in some manner to provide a longer life. I've always heard that with out the saver on the magnet, if the magnet was hit or dropped it would lose magnatism also.
The sliding the magnets off the charger may not be accurate since on the Hit and Miss engine the magnet is being disconnected every time the ignition fires. Just my thoughts and I didn't stay at a Holiday Inn Express last night so I may be wrong on some of my thoughts.
What I do is the following :
I recharged the magnets OFF the flywheel, before charging they have about 0,6 kg, and after 6 kg.
I dont use keepers !!!
After putting all together as: The flywheel,coilring ,crankshaft,pistons that is the time to check your AC volt.
By turning the engine with a self made crankhandel as fast as you can you should have3.5 to 4 volt AC
After all, when the engine is running I always have about 35 - 40 volt AC at high speed
Greetings from Holland
I do magnet charging and from all the research material I have accumulated and read - it is adventageous to install keepers after charging.
Got this photo off the net maybe the forum or Tbay, it is supposed to be new old stock magnets from a dealership in their shipping crate. Hope this works it's my first time posting a picture. Jim
Jerry VanOoteghem, the magnets are not arranged N-S-N-S-N etc.
The proper sequence, either shipped or installed is N-N-S-S-N-N etc.
Reference the Model T Service manual, paragraph 284.
Darn, I knew I would get that wrong! Seems like I've got a 75% chance of getting a 50-50 chance wrong!
Thanks for pointing that out Kenneth.
If you have a 50-50 chance, the odds are 10 to 1 you are wrong.