suitable SG magnet

[Erol27]

Hello everyone,

I bought some small neodymium magnets, and then learnt that they're too strong to use for Schoolgirl motor, so now I'm looking on eBay for some suitable ceramic type.

I've found 2 candidates, shown in the following links:

Jaycar Electronics - Search results LM1614

(item code LM1614 from Jaycar)

-and-

Buy 200 Ceramic (Ferrite) magnets 20mm x 3 mm | eBay

("Buy 200 Ceramic (Ferrite) magnets 20mm x 3 mm" from eBay seller "magnetic world")

Is there a specification of the magnet that we shouldn't exceed? Ie. to be confident it's not too strong?

Also, does rectangular or round play a better role?

Thanks

[Neight]

Hello everyone,

I bought some small neodymium magnets, and then learnt that they're too strong to use for Schoolgirl motor, so now I'm looking on eBay for some suitable ceramic type.

I've found 2 candidates, shown in the following links:

Jaycar Electronics - Search results LM1614

(item code LM1614 from Jaycar)

-and-

Buy 200 Ceramic (Ferrite) magnets 20mm x 3 mm | eBay

("Buy 200 Ceramic (Ferrite) magnets 20mm x 3 mm" from eBay seller "magnetic world")

Is there a specification of the magnet that we shouldn't exceed? Ie. to be confident it's not too strong?

Also, does rectangular or round play a better role?

Thanks

Hello Erol27,
first off
These Bedini energizers are great fun to build and tune, and a great project to start off with and learn about generating energy
If you have a Radio Shack near you, they sell stacks of ceramic magnets that are nearly identical to the one's sold in the kits that John Bedini himself approves of. They are pretty cheap from radio shack, and you wouldn't have to wait out shipping.
I would use rectangular magnets, though I am sure the round one's would work just fine. The rectangular one's you can orient to give the sharpest on/off time of the magnet passing over the coil. If I remember correctly, you want to find #8 ceramic magnets, and buy enough to space them evenly around your rotor.
also, VERY IMPORTANT!!!! Get some good epoxy to fix them to the rotor, and get some very strong tape to hold them down as well. Depending on your rotor size, you will likely be dealing with several hundred to over 1k RPM! These mags can and will fly off the rotor, and you don't want to get hit by that!
good luck with your build, and don't be afraid to ask lots of questions! this is a great forum, and it's where I found the advice I needed to get my first motor spinning
hope that helps

N8

Edit: here is a link to the mags RS sells - High-Energy Ceramic Magnet - RadioShack.com