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Solenoid Coils.


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maddox



Joined: 21 Dec 2006
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Solenoid Coils.

Over here we normaly use the Burkert 5404 with 24V coil.

But a lower voltage coil would be great.

I'm not an electrical guy, so, what is needed to make one?

A thin wall non magnetic tube that fits over the "plunjer" and a load of thin insulated copper wire....
But after that? Is it just a long single winding? How much and how thin is needed?
Is long and thick better than a thin and shorter wire? Total resistance can be the same, but how goes the magnetic force then?

Post Mon Jul 27, 2015 9:40 pm 
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marto
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Just buy the 12V clone off Ali express for $15
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Post Mon Jul 27, 2015 9:41 pm 
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maddox



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I just grinded one open,to look how much smaller it can be made.

There is a huge scope for improvement there.

Post Mon Jul 27, 2015 9:42 pm 
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Glen
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Whats inside it? iron core or just air wound?

if air wound - http://www.daycounter.com/Calculators/Coil-Physical-Properties-Calculator.phtml
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Post Mon Jul 27, 2015 10:40 pm 
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maddox



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It's a huge block of plastic, with a U shaped steel bracket holding the coil and reinforcing the plastic.

The coil does not have a core in itself, the stainless steel "tube" on top of the valve fits comfortable in the coil.

Post Tue Jul 28, 2015 11:35 am 
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Nick
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As well as getting it working on 12V, will it improve performance if the valve opens a bit quicker? The 24V coil has a really low current rating so if you use thicker wire and that calculator, the current and the magnetic field strength can be increased, pulling the solenoid core into the coil faster. Since the coil is only energised for a short time, you can increase the current quite a bit without overheating it.
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Post Tue Jul 28, 2015 12:02 pm 
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Glen
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quote:
Originally posted by maddox:
It's a huge block of plastic, with a U shaped steel bracket holding the coil and reinforcing the plastic.

The coil does not have a core in itself, the stainless steel "tube" on top of the valve fits comfortable in the coil.


interesting, might have a go of winding a new one tonight then. 200 winds of 24g at 12v should do the trick.
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Post Tue Jul 28, 2015 12:32 pm 
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Valen
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wind it with the thickest you can easily fit, limit it with a resistor, that way you can tune it more easily perhaps?
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Post Tue Jul 28, 2015 1:56 pm 
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Glen
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Heres a shameful example wound with a powerdrill after work.

450 turns of 24g 0.5mm diam wire. 1.6-1.7 ohm resistance. Draws about 9 amps at 12v with some extremely sloppy winding lol.

Pulls closed at 5.5v holding it in a vertical position and 6v with the whole valve assembled with springs. Will test it under pressure tonight Smile

https://www.youtube.com/watch?v=B353iuWP5Vo&feature=youtu.be
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Post Wed Jul 29, 2015 3:57 pm 
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maddox



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9 amps. That's not easy to command with a commercial RC relays, unless cascading.

On the other hand, the Turnigy switch promises 10 amps 30V max.

Post Wed Jul 29, 2015 4:44 pm 
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Glen
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I've just been using these on an arduino - Whether they live up to that promise we'll see, but for 25ms on time i suspect they may.

http://www.freetronics.com.au/products/n-mosfet-driver-output-module#.Vbh4g_mqqko

Don't forget you could wind one to be the same wattage as the stock coil at a lower voltage. I just didn't have the patience to put 1000 turns + on it lol Smile
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Post Wed Jul 29, 2015 4:55 pm 
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Glen
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okay just tested him then, heated the bottle up to about 700psi - Valve fired between 11-12v, after the first shot it was happy to fire down to 10v. This one would be sweet off a 4s lipo Smile
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Post Wed Jul 29, 2015 5:43 pm 
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Nick
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Wind the coil with more turns and this Pololu RC switch should control it perfectly: https://www.pololu.com/product/2803



Small and cheap, just what you need,
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Post Wed Jul 29, 2015 7:02 pm 
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miles&Jules
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Cool... that homemade one looks amazing…. Do solenoids always suck inward like that? i bought one at the dump…but thought they popped out rather than in…so maybe it does work Embarassed
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Post Thu Jul 30, 2015 10:27 am 
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Nick
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Solenoids always pull the iron core into the coil - but if the core has a non-magnetic extension, that part can be pushed out the other side.
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Post Thu Jul 30, 2015 10:36 am 
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