Magnets with Halbach array in an AC generator

[Manuel12]

As a project, I am demonstrating electromagnetic induction by making an AC generator. The magnets I currently have access to are very strong neodymimium countersunk magnets, but I noticed that they utilise a Halbach array. I am aware that this means the magnet has alternating N-S poles spaced together, creating a stronger field on one side.

I assume the magnet and rotor would be something like the diagram below (there might be more "central" fields in mine)

Given this, can the magnets be used in a 2-phase AC generator? If yes, how would the surrounding coils have to be oriented?

 

[Baluncore]

Welcome to PF.

The PM field for an alternator rotor needs to radiate large N and S fields outwards, alternating through the coils as it rotates. You show a rotor with only half that field, rotating the array sideways. Maybe the Halbach array is not the best way to go.

We need a better picture of the countersunk magnets available, with the poles marked on the surface, then construction of the rotor can be optimised.

 

[Manuel12]

Not sure if it's useful, but these are the magnets: https://www.amazon.nl/gp/product/B08K39Q1DL/

The flat side of the magnet is weaker, and the side with plastic protection is stronger

 

[Baluncore]

The countersunk magnets appear to be designed to hold tight onto a flat metal plate. That looks like one pole is around the centre hole, with the other pole around the outside of the same face, with the gap between poles filled by plastic. You can check that by feeling the poles with an iron wire like a paper clip, and/or a magnetic compass to identify the polarity.

I don't think those magnets can be used conveniently for a two pole alternator.

 

[Manuel12]

The countersunk magnets appear to be designed to hold tight onto a flat metal plate. That looks like one pole is around the centre hole, with the other pole around the outside of the same face, with the gap between poles filled by plastic. You can check that by feeling the poles with an iron wire like a paper clip, and/or a magnetic compass to identify the polarity.

I don't think those magnets can be used conveniently for a two pole alternator.

I think I might have to order a regular 2-pole cylindrical magnet then. Thanks for the reply!

 

[Manuel12]

The countersunk magnets appear to be designed to hold tight onto a flat metal plate. That looks like one pole is around the centre hole, with the other pole around the outside of the same face, with the gap between poles filled by plastic. You can check that by feeling the poles with an iron wire like a paper clip, and/or a magnetic compass to identify the polarity.

I don't think those magnets can be used conveniently for a two pole alternator.

Do you think these magnets could work?: https://www.amazon.nl/gp/product/B00F9A0P6U/

The N-S poles are on each of the 40 mm x 20 mm sides

 

[Baluncore]

Do you think these magnets could work?

Yes.
If the rotor shaft will pass through the rotor, then you will need two magnets, one on each side of the shaft. You will need a rectangular block of iron between the two magnets, with a hole drilled to take the shaft.

A segment of an iron cylinder should be attached to the outside of each magnet to make the outer surface of the rotor poles a cylinder. That will reduce the gap between the rotor and the stator.