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Wind vane project

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Frances IoM26/12/2017 21:42:51
1395 forum posts
30 photos
I presume the aluminium (or any conductor) disk rotating between the N-S poles of a magnet acts as a single turn armature, the current induced varying with the speed of rotation- wch current also then acts as a motor current wch would turn the armature in the contrary direction thus giving a damping effect that varies with the speed
Peter Krogh27/12/2017 07:26:50
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228 forum posts
20 photos

A simple eddy current brake. The ready availability and low price of Neodynium magnets has made such dampers easily affordable for us to play with. I love thinking about some new gadget to mess with.....

Pete

Tractor man27/12/2017 08:40:53
426 forum posts
1 photos
So applying the principle of an eddy current brake to the indicator pointer, I would attach a non ferrite disc to the pointer shaft behind the dial and place two strong magnets either side of the disc. Would this provide an eddy current effect at the low speed of the pointer shaft i.e. damping sudden changes in direction of the vane in the roof? Would the use of kilopoise lubricant in the pointer shaft be a similar method of damping such movements? Mick
Michael Gilligan27/12/2017 08:51:02
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23121 forum posts
1360 photos
Posted by Peter Krogh on 27/12/2017 07:26:50:

A simple eddy current brake. The ready availability and low price of Neodynium magnets has made such dampers easily affordable for us to play with. I love thinking about some new gadget to mess with.....

Pete

.

I had only thought of pemanent magnet eddy current braking in lightweight applications, before ... and was astonished to see Circular Saws and Roller Coaster Rides mentioned on the Wikipedia page: **LINK**

https://en.m.wikipedia.org/wiki/Eddy_current_brake#Disk_eddy_current_brakes

Always good to learn something new yes

MichaelG.

Ian S C28/12/2017 11:01:52
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7468 forum posts
230 photos

No remote indicator or anything fancy, here's mine.

Ian S C

004 (640x480).jpg

duncan webster28/12/2017 11:28:39
5307 forum posts
83 photos

Eddy curent brakes are used in Brille clocks to control pendulum swing and in Wixie angle gauges to damp the pendulum. They sound ideal for a wind vane. A friction damper would be prone to sticking just slightly off true position. If using 2 magnets just be sure that they are not in opposition

Tractor man28/12/2017 19:19:00
426 forum posts
1 photos
So.i have made a small scale model of the proposed vane to test some theories. The bearing tube and thrust bearing work very well so that I have an output shaft I can use to drive the indicator.
The actual pointer turns very smoothly but I didn't balance it and I'm not sure how much of an impact that will have. It certainly turns into the wind due to the relative size difference of the arrow and tail pieces.
I ordered a set of cardinal letters from e pay and will fit them when they arrive. Then I'll post some images.
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