STEORN DEMO LIVE & STREAM in Dublin, December 15th, 10 AM

[Airstriker]

Toroid radius = 3 cm
Turns = 37
Coil radius = 2.5 cm
Permeability = 55,000
+++++++
Inductance = 985.60 mH

[Edit:]  The above represents a toroid that is 0.5cm in thickness.

You cannot have coil's radius that is almost the same as toroid's radius. The equation that tells you the Inductance is only valid for a very small ratio of coil's radius vs. toroid's radius. I'm just fed up with correcting your thoeries all the time ;]

[PaulLowrance]

Toroid radius = 1.5 cm
Turns = 37
Coil radius = 1.0 cm
Permeability = 168,000
+++++++
Inductance = 963.38 mH

The above represents a toroid that is 0.5cm in thickness.

Hi GB,

Okay, there's something very different with what they call coil radius. Also it's nice if they had toroid height as well.

Anyhow, after trying numerous times to get that calculator to agree with real measurements, I've failed, so I found a calculator that is very clear in what is what, and also is has toroid height.  Best yet, it's in agreement with real measurements -->

http://www.mantaro.com/resources/impedance_calculator.htm#toroid_inductance

So the first time I entered in the Steorn toroid dimensions (close as I can see) and using a permeability of 1 million, here is the results -->

Toroid height (length) = 300 mils (1 mil = 0.001 inches)
Outer diameter = 1100 mils
Inner diameter = 700 mils
Permeability = 1000000
Number of turns = 37
+++++++++++
Results = 943001874.832 nH = 0.94 Henry 
[/]

[Airstriker]

Nice find Paul !

[gravityblock]

You cannot have coil's radius that is almost the same as toroid's radius. The equation that tells you the Inductance is only valid for a very small ratio of coil's radius vs. toroid's radius. I'm just fed up with correcting your thoeries all the time ;]

Why you can't have a coil 0.5 cm in thickness when the total radius is 3.0 cm.  Lol

Once again, go to the calculator link and take a look at the illustration.  It clearly shows you how the coil radius and toroid radius is calculated.  If you follow these instructions then it is possible.

Paul said "Okay, there's something very different with what they call coil radius."  Don't blame me for what they call coil radius. lol

The toroid would be 0.5 cm in thickness when the toroid radius is 3.0 cm and the coil radius is 2.5 cm (3.0 - 2.5 = 0.5) according to how they measure the toroid and coil radius.  I even put a little edit note at the bottom of the post to avoid confusion, but yet that didn't help you to understand the measurements.

You prove once again you have poor reading comprehension.

GB

[PaulLowrance]

Hi Paul L.,

Could you please double check the permeability of our Magamps.  The people at Elna mentioned a permeability of 90,000.  You mentioned 1 million.  I tried to find it in the spec sheet but could not.  We need to know this exactly, to know the correct number of winds.   

Thank you,

Bruce

Hi Bruce,

There are two types of 2714A material for non-custom orders. One is transversely annealed, which has a permeability of 80,000. The other longitudinally annealed, which has a permeability of 1 million.

This page tells you that MAGAMP is square loop -->

http://www.metglas.com/products/page5_1_6_4.htm


This page that shows the 1 million permeability of an annealed 2714A core -->

http://www.metglas.com/products/page5_1_2_6.htm


I went through this whole mess with Metglas years ago. It's confusing, lol.