Neodymium Magnets: Does Size Matter?

In summary, an alternator works by regulating the output voltage of the device using field coils. If you were to replace the normal magnet with a neodyniam, the field coils would be smaller, resulting in less air resistance and an increase in efficiency.
  • #1
Qaiphyx
92
0
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.
 
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  • #2
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
 
  • #3
capthook said:
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?
 
  • #4
Qaiphyx said:
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.
 
  • #5
Qaiphyx said:
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.
 
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1. What is the difference in strength between large and small neodymium magnets?

The strength of a neodymium magnet is directly related to its size. Generally, larger magnets have a stronger magnetic field and can exert more force than smaller magnets. However, the strength also depends on the specific grade of the magnet, with higher grades having a stronger magnetic field regardless of size.

2. Are larger neodymium magnets more expensive?

Yes, larger neodymium magnets are typically more expensive than smaller ones due to the increased materials and manufacturing costs. However, the price also depends on the grade and type of magnet, with some larger magnets being more affordable than smaller ones.

3. Can I use a smaller neodymium magnet instead of a larger one in my project?

It depends on the specific project and what you are trying to achieve. If the smaller magnet has a strong enough magnetic field to fulfill the desired function, then it can be used instead of a larger one. However, if a larger magnet is required for the project to work properly, then a smaller one may not be suitable.

4. Are there any safety concerns with handling larger neodymium magnets?

Yes, larger neodymium magnets can be very strong and may pose a safety hazard if not handled properly. They can attract to metal objects and may cause injury if they snap together or if a finger gets caught between them. It is important to handle all magnets with care and follow proper safety precautions.

5. Do neodymium magnets lose their strength over time?

Yes, neodymium magnets can lose their strength over time due to a process called demagnetization. This can occur if the magnet is exposed to high temperatures or strong magnetic fields, or if it is dropped or bumped. However, with proper care and handling, neodymium magnets can retain their strength for a very long time.

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