Magneto charging

[Jeff Silvey]

I have a mag charger that charges a wico, webster mags on old engines. I have recharged some through for years.
My question can I recharge a J4 plus a H4 mag coils? Some members know what I have on charger. I have had this unit for 20+ years.
Thanks

[John *.?-!.* cub owner]

Isn't it actually the magnets rather than the coil that needs charged? I have not heard much of the H4 and J4 magnetos needing recharged.

[Eugene]

Remagnetizing the magnets?

[Rick Spivey]

Possibly an H4, but the J4 has a magnetized armature. While I'm sure there is a machine somewhere that could re-magnetize one, most older machines likely would not. And yes, it's the magnets that get magnetized, not the coil. I have personally run across two J4 magnets where the armature had lost its magnetic attraction. They are called "permanent" magnets meaning they weren't expected to need re-magnetizing over time; however, if stored incorrectly or placed near an electrical or magnetic source, it would be possible to damage one. Those armatures were made from "alnico", which is considered a permanent magnet, since the magnetic attraction comes from the crystal alignment, and not from an outside source such as your magnetizer.

[Jeff Silvey]

Thanks on all the info. Make sense.

[John *.?-!.* cub owner]

Rick, electronics is my field of work, and the biggest danger to a permanent magnet is storing it close to a large transformer. The magnetic field it creates is quite sufficient to demagnetize even a strong magnet like the J4 armature.