4 replies to this topic

[Dave_12]

How often should a cobalt magnet setup have the magnets re-zapped?

[Bill Seitz]

It takes a wicked powerful industrial magnetizer costing thousands of $$$$ for neo's or cobalts, and I'm not aware of anyone even offering the service. I have cobalts that are years old, never been re-magnetized, and seem no worse for it.

[stoo23]

Whilst I guess, there Must be Some 'losses' over time and use with Cobalt magnets, it is probably not that bad,.. (well as compared to other magnetic types), as Cobalt specifically, does not suffer particularly from de-magnetization due to shock, or heat, (as its Curie temperature is very high) and exhibits extremely high magnetic anisotropy, giving it very high coercivity and (on an atomic level), due to the  'spin' and quantity  of it's un-paired electrons, also exhibits high Remanence.

 

It does require a relatively high powered charging device (Zapper), as Bill suggests but Nothing like that which is required for Neodymium, which requires far greater power.

 

When we had our NdFeB magnets made here many years ago, I could only find one company in NSW, that actually had the ability and equipment to charge them adequately and rather fortuitously to also do so Radially

 

Cobalt charging is not nearly as difficult, compared to Neodymium.

Whilst I believe the guy that did ours, is now retired, the company still exists and if you really need, I can probably find the contact information for you. They helped one of the local drag racing guys (who makes his own motors) here a while ago

[Dave_12]

Stoo Gill Andrews has a magnet zapper for Cobolts and balances armatures .  
I think that is where most people in Australia are sending their gear these days. 

[stoo23]

OH, ok, I was Not aware Gil could do that. I know a lot of people have Stuart Bach do their balancing.

Be interesting to find out if Gil can do 'Radial' charging.