How to work with images / Re: How to attach pictures
« Last post by JW on February 17, 2024, 10:48:30 AM »Im just happy no one else is having this problem
The most important neighbor in my case is the wife.
The nastiest noise I've ever had was when the top of a tube was being rubbed. Kind of like the sound a glass makes when you wet your finger and do circles across the top. Only about 1,000x louder.
Isn't the RPM area for a given turbine only determined by the rotor size? I understand that a wind turbine harvests the most energy from the wind if it operates at the optimum tip speed ratio (typically around 7 for a three-blade HAWT). If the wind speed is 10 m/s, the tip speed should ideally be 70 m/s, which corresponds to a specific RPM for a given rotor size. A small turbine would have to spin faster to operate at TSR=7. This logic is further elaborated in my original post. I think this is the core of my problem, so please tell me if I'm missing something here.
Thank you for the generator suggestion MagnetJuice. I have also been looking at this one:
ebay.co.uk/itm/235042332008?chn=ps&_ul=GB&var=534977374051&norover=1&mkevt=1&mkrid=710-169684-097358-0&mkcid=2&itemid=534977374051_235042332008&targetid=293946777986&device=c&mktype=pla&googleloc=1010976&poi=&campaignid=20649918451&mkgroupid=151788312862&rlsatarget=pla-293946777986&abcId=&merchantid=6995734&gclid=Cj0KCQiAw6yuBhDrARIsACf94RV3voAhQUyhNRR0LcWsCQCp3uWbPtWYMEVdzHyCNEoHbJthoCFvIxwaAqJVEALw_wcB
I have also another question. Some of you are talking about the cut-in speed where the generator will output 12V. Is there a problem with just using a buck-boost converter?
Greetings,
Lars Erik
When I try to upload a pic im getting "fakepath" in the link to uploadIntended.
so I have managed to keep my neighbor's from revolting against me by overdosing both bearings with WD40.
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With air core coils cogging isn't an issue to worry about!
The way your top and bottom allow leakage out of the blade is a must. Its okay to have holes in your blades, preferably to only induce enough drag to get the result you want. Human nature leads us to create cups, but if the air cannot leak then stagnant air gathers at the blade. The leakage allows stagnated air to clear the blade. The barrel-conversion savonius designs often prevent this leakage and it kills efficiency. The air should flow around the blade rather than be stopped/blocked by it. You want that clean air to be accessible to the blade.
NOPE! That is a much much smarter Bruce , his moniker was Bruce DownUnder.
At the end of the article it states special thanks to Bruce! Was that you BruceS by any chance?
pfff a sigh of relieve.
I had the probe on wrong and also the wire ends weren't sanded enough to make the probe latch reliably.
(Attachment Link)
So false alarm thus far. Still no signs of interference.
BTW Mary, if all results are already in of this design, Ed suggested me to take a look at, then how can I be of help giving those a once over?
Is it that perhaps making use of a tesla meter can give some new insights?
Anyways may I please have the link to where this work has been done before me so I can learn and potentially see what Ed meant with how I can be of benefit?
{1}the reason why the waves are rather erratic is most likely because the wires were vibrating as they were banged at while the magnets spun over them.{/1}
With air core coils cogging isn't an issue to worry about! Why iron core has been tried and not used.
For what you are doing get an F&P setup here http://www.randysworkshop.net/order.html and use it to play with your mechanical design, once that is perfected THEN see if you can improve on the alternator part of the equation! The F&P as is will crank out some decent voltage at low RPM, I spun one up by hand and lit a 100 watt 120 volt light bulb! 60RPM = 18 volts! https://www.fieldlines.com/index.php?topic=149388.0 Gear up your design to spin it faster and see better output! Stack 2 or even 3 assemblies if you have the torque and series it for low RPM higher voltage...
Playing with an F&P will teach you about cogging too and how much torque it takes to over come it.
The rotor setup that you build for testing should have only 8 magnets per disk.
The magnet wire should be between .9mm and 1.3mm. No smaller or bigger than that. That wire size can also be used for the big alternator for your VAWT.
The magnets that you showed on the links are the wrong proportions.
A magnet like this will work for testing and will also work for your big multipole alternator for your VAWT.
https://enesmagnets.pl/en/permanent-magnets/neodymium-sintered/block-magnets/50-x-20-x-20-n35-ndfeb-neodymium-magnet.html
pfff a sigh of relieve.
I had the probe on wrong and also the wire ends weren't sanded enough to make the probe latch reliably.
(Attachment Link)
So false alarm thus far. Still no signs of interference.
BTW Mary, if all results are already in of this design, Ed suggested me to take a look at, then how can I be of help giving those a once over?
Is it that perhaps making use of a tesla meter can give some new insights?
Anyways may I please have the link to where this work has been done before me so I can learn and potentially see what Ed meant with how I can be of benefit?
{1}the reason why the waves are rather erratic is most likely because the wires were vibrating as they were banged at while the magnets spun over them.{/1}
in the meantime I have already a tentative conclusion that indeed a 1mm wire is the way forward as opposed to smaller.
What I did is have a coil of 1mm wire with 10 winds and a coil of 0.4mm wire at 40 winds.
Coil shape was narrow like in the double density tests.
When at around 8 Hz the 0.4 coil did around 160mV and the 1mm coil did around 48mV.
Then I hooked up each coil separately to the CVCC and fed in the voltage level they produced at 8Hz.
Then I measured the field strength at 10mm distance on both.
The 1mm coil had 16mT and the 0.4 coil had 8mT.
Unless I am tackling this wrong I think we have a clear winner {1}for when winding narrow.
But in the process just now of trying a coil shape that is matched to the magnets at 3.75 interval then this happened.
(Attachment Link)
at 3.8 Hz the 10 winds 1mm coil did around 100mV and the 40 winds 0.4 coil did around 410 mV.
at 100Mv DC the 10 winds 1mm coil produces a field of 25mT in the center at 10mm distance. the field drops sharply when moving to the coil legs.
at 410mV DC the 40 winds 0.4 coil also produced a field of 25mT in the center at 10mm distance. the field drops sharply when moving to the coil legs.
Now I think it is a matter of finding the sweet spot of how thick we can get wires. 1mm might indeed be the absolute minimum.
{/1}
{2}this website actually does tell a lot about the coil and shape. so something to hold on to and work from in terms of dimensional reference point.{/2}
{3}albeit that the coils seem to vary from picture to picture. So I am not sure which one was intended for the rotor configuration and which KW rating was attributed to it.{/3}
Thank you Ed,
This means the world to me!
So I have been able to figure out where that image came from or at least determine that it is also used by a Vietnamese seller of PMA kits.
https://www.blogdiengio.com/p/nhan-lam-bo-kit-may-phat-ien-500w-1kw.html
here is a translation of what is written in the context of that image
"Get generator kits for 500w, 1kw, 2kw, 3kw, 5kw
Do you want to make your own generator but don't have time or are you simply lazy? Let us help you. The machines we make are close to the capacity and suitable for where you live. Please contact Lam Nguyen"
My complaint to sellers like this and to the endless videos being shared online that they always fail to mention how it was determined to have a certain rating.
That was the origin of my question to you in the PM magnets to watts.
Let alone it says nothing about the coil shape and the reasoning behind that coil shape.
And of course I trust you and I will listen to you and will set this up I just fear the RPM need to be really high in order for the voltage produced to be of any use.
But as you stated I do lack a lot of understanding yet so let us just go at it and see where this leads us.
So step 1 would be is to eyeball the dimensions of this setup yes?
I am having difficulties guessing as I do not see a clear reference point to work from.
Step 2 would be sourcing these type of magnets. And I can I have already checked.
https://www.supermagnete.nl/blokmagneten-neodymium/blokmagneet-40mm-40mm-20mm_Q-40-40-20-N
if we opt for a 60kg holding force
or we can go a little stronger with something like this
https://www.supermagnete.nl/blokmagneten-neodymium/blokmagneet-50.8mm-50.8mm-25.4mm_Q-51-51-25-N
Now obviously the relationship between cost and power is lost but that does not matter in the pursuit of science.
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People can't seem to get their head wrapped around that idea.Yes, for you and me it's obvious. For folks who live in high-rise apartments, not so obvious.
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