Neodymium Magnets: Does Size Matter?

[Qaiphyx]

They pull a lot of pounds in ratio to their size, I was wondering if it would make any difference in the energy output if you replaced the normal magnet with a neodyniam.

 

[capthook]

It depends...

A stronger magnet will of course create a stronger flux, but it will create additional drag due to Lentz law and "cogging". As such - the air gap will have to be increased to keep things "equal", or power increased - else the torque and RPM's will decrease, resulting in lower output.
If building from scratch - I would use neos. Reworking an existing unit will probably not be benificial as it would (should) have been designed to work best with the current flux.

CH

 

[Qaiphyx]

It depends...

A stronger magnet will of course create a stronger flux, but it will create additional drag due to Lentz law and "cogging". As such - the air gap will have to be increased to keep things "equal", or power increased - else the torque and RPM's will decrease, resulting in lower output.
If building from scratch - I would use neos. Reworking an existing unit will probably not be benificial as it would (should) have been designed to work best with the current flux.

CH

So then if you have a smaller neo at same strength as a normal magnet if would have less air resistance, slightly increasing efficiency right?

 

[capthook]

They pull a lot of pounds in ratio to their size, I was wondering if it would make any difference in the energy output

If you replace them with neos of equal gauss rating, rather than size - the magnets would be smaller. So yes - less air resistance, as well as weight, could result in an increase in efficiency. The output wouldn't increase if running at the same RPMs as before - but the input might decrease.

 

[Phrak]

They pull a lot of pounds in ratio to their size, I was wondering if it would make any difference in the energy output if you replaced the normal magnet with a neodyniam.

I googled "how does an alternator work". They doen't seem to use permanent magnets, but field coils. By controlling how much current flows through the field coils the output voltage of the alternator can be regulated.