# Magnet question: Gauss value vs. magnetic stregth



## Ichabod (Sep 5, 2010)

when looking at magnets how important is the Gauss value (surface field strength) versus the magnetic force of the magnet. can i assume that in the application of reel magging the surface field strength is extremely important. does this value represent the width of the field of magnetism?

Thanks, Chris


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## Hudak (Sep 10, 2007)

Ichabod said:


> when looking at magnets how important is the Gauss value (surface field strength) versus the magnetic force of the magnet. can i assume that in the application of reel magging the surface field strength is extremely important. does this value represent the width of the field of magnetism?
> 
> Thanks, Chris


Since we are talking about aluminum spools, generally, I would think the magnetic force of the mag, as you have described, would be a useless variable. Since we are controlling a spool via eddy currents, it sounds as if the Gauss value may be a little more important. Although I completely appreciate the in depth question, I sincerely doubt _most_ of us have done the required research to satisfy your inquiries.


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## lil red jeep (Aug 17, 2007)

Yeah, what he said! I guess.


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## Drumdum (Jan 6, 2003)

Freind of mine,mechanical engineer,posted this on another forum years ago when everyone had to have a magged reel.. I'm sure he was correct in what he was saying and it involved a bunch of equations,facts on how it works and the in's and out's of an alluminum,or graphite spool.. By the time you had finished TRYING to read it,was like sitting in a graduate class of college for a phisics course or something.. Way over what my little highschool graduate peabrain could master....


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## seajay (Dec 18, 2005)

Ok a gauss is the cgs unit of measure of a magnetic field, which is the field of force produced by a magnet,which is detected by the force it exerts on another magnet.Which is known as magnetic flux (Phi) So the higher the G value the stronger the magnetic field.
A small iron magnet is around 100 gauss an MRI Electromagnet is around 30,000 gauss.
So to answer your ? Yes to the first part. That is why people add a different amount of mags to there reels. for static mag. one could use a single adjustable mag. and by changing the air gap change the amount of Flux.
Now different materials will produce a stronger magnet.And the size of the magnet does not mean that it is a stronger magnet.
Now if I have confused you more,I suggest getting a book on Electrical Theory.


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## Mark G (Nov 15, 2004)

http://www.leevalley.com/us/shopping/Instructions.aspx?p=54198


THis is an excerpt from Lee valley on their magnets-- the link above should get you to the drawings. 







> Making Magnets Work Harder
> 
> Magnets do their best work when focused. The natural field of a magnet is polar radiating loops. Disc magnets have equal fields (Figure 2). The trick is to get both fields working for you.
> 
> ...


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## Charlie2 (May 2, 2007)

*Magnets*

Thanks for the Lee Valley link: Now, I can quote something that will make me to appear half smart.

I just use an Aluminum spool, magnet cups and mount the magnets opposing the polarity of them. Works for me.

GOS has probably the best site on magging reels that I know of. C2


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## Ichabod (Sep 5, 2010)

*Thanks to all.*

.


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## rattler (Jul 3, 2004)

Ichabod said:


> when looking at magnets how important is the Gauss value (surface field strength) versus the magnetic force of the magnet. can i assume that in the application of reel magging the surface field strength is extremely important. does this value represent the width of the field of magnetism?
> 
> Thanks, Chris


yes.


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## kingfisherman23 (Dec 14, 2003)

Both measurements are relevant to the field of magged braking.

The magnetic field strength (ie oersted, ie H-field measurement) is an indicator of the strength of the magnet. It does not take into account the effect a magnet will have on another magnetic field.

The magnetic induction (ie Gauss measurement, ie B-field measurement) is the influence that the magnet will have on other magnetic bodies and/or fields. This is relevant when looking at how much of an effect a magnet will have when placed near the rotating spool. A small iron magnet produces about 100 Gauss, while a similarly-sized rare-earth (neodymium) magnet produces about 2000 Gauss.

A Gauss and an Oersted are related, and in a vacuum 1 G = 1 Oer. While a still spool produces no magnetism in response to the magnetic field (creating a K-value of 1), a rotating spool will produce an electrical and magnetic response in opposition of the field that crosses the spool according to Lenz's Law.


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