Author Topic: Solenoid driven V8 - Work in progress  (Read 9924 times)

Offline PStechPaul

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Re: Solenoid driven V8 - Work in progress
« Reply #15 on: September 27, 2016, 09:35:16 PM »
The brass (or other metal) tube on which the coil is wound, acts like a shorted turn of a transformer. Thus, when DC is applied to the winding, the coil will not exhibit much inductance, so the current will just about instantly reach a level determined by the resistance of the wire. This may enable the magnetic field to maximize quickly, which may be helpful. But if the plunger is a permanent magnet, it will resist movement due to Lenz's law:

http://www.iflscience.com/physics/what-happens-when-you-drop-magnet-through-copper-tube/

As suggested, slitting the tube should help, although perhaps not as much as using a non-conductive material. If the tube with a slit is supported by conductive material on the ends, some current will still be induced, and may cause some force on the plunger.

Offline Don1966

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Re: Solenoid driven V8 - Work in progress
« Reply #16 on: September 27, 2016, 10:53:15 PM »
As suggested, slitting the tube should help, although perhaps not as much as using a non-conductive material. If the tube with a slit is supported by conductive material on the ends, some current will still be induced, and may cause some force on the plunger.
Adding Metal rings to the ends of the coils will put it back to the same position as before you slit it. You have formed a closed circuit and eddy current with effect it, so will the magnet moving in it.

Don

Offline PStechPaul

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Re: Solenoid driven V8 - Work in progress
« Reply #17 on: September 28, 2016, 12:48:52 AM »
Except that the slit will prevent the current from flowing around the tube, which is what causes the force in the direction of motion of the magnet. It will flow at an angle toward the end caps, and the force will be a vector with varying effect from the center to the ends of coil. So if the end caps are metal, they should be insulated from the tube. Since the solenoids have already been wound, slitting the tube is not really an option. I don't know if using a magnet for the armature will be more problematic or better than a steel slug. It should be possible to test one of the solenoids before proceeding any further - no sense worrying about a problem that might not even be significant. ;)

I found the video showing the build for the V12 engine by davidrobert2007:

<a href="https://www.youtube.com/watch?v=k64LixRRfEw" target="_blank">http://www.youtube.com/watch?v=k64LixRRfEw</a>

He used off-the-shelf solenoids that have a steel frame and steel plunger. The coil seems to be wound around a cylindrical steel sleeve. This essentially forms an electromagnet with one pole in the middle, and the other on the outer steel frame. The plunger serves to increase the magnetic flux as it is pulled into the cylinder.

http://www.solenoidcity.com/solenoid/manual/construction/construction.htm

http://www.ebay.com/itm/ZYE1-0530-DC-12V-1A-10mm-Stroke-Push-Pull-Type-Open-Frame-Solenoid-TS-/172173195817
ZYE1-0530 DC 12V 1A 10mm Stroke Push Pull Type Open Frame Solenoid TS
« Last Edit: September 28, 2016, 01:45:11 AM by PStechPaul »

Offline Noitoen

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Re: Solenoid driven V8 - Work in progress
« Reply #18 on: September 28, 2016, 10:52:45 AM »
There is no problem in using a brass tube in a dc coil. The problem is with the moving magnet which induces an eddy current in the brass pipe. If you fill the pipe with magnets nothing happens but if you move the magnets back an forth, this will heat up the pipe quickly. The same will happen if you feed the coil with ac current.

Offline Ian S C

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Re: Solenoid driven V8 - Work in progress
« Reply #19 on: September 28, 2016, 12:47:23 PM »
I have quite a collection of solenoids, and two solenoid motors, they all have brass tubes in them.
Ian S C

Offline Don1966

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Re: Solenoid driven V8 - Work in progress
« Reply #20 on: September 28, 2016, 04:00:18 PM »
I have quite a collection of solenoids, and two solenoid motors, they all have brass tubes in them.
Ian S C
Yes Ian that is not uncommon for a DC Solenoid, but it has a metal armature or plunger not a magnet.

Don

Offline cfellows

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Re: Solenoid driven V8 - Work in progress
« Reply #21 on: September 28, 2016, 04:39:38 PM »
Solenoids also don't normally cycle with the frequency that a solenoid motor would require.  I should think repeated, rapid switching on and off of the DC current would cause heating similar to that with AC current.

Chuck
So many projects, so little time...

Offline Don1966

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Re: Solenoid driven V8 - Work in progress
« Reply #22 on: September 28, 2016, 05:33:18 PM »
Solenoids also don't normally cycle with the frequency that a solenoid motor would require.  I should think repeated, rapid switching on and off of the DC current would cause heating similar to that with AC current.

Chuck
True Chuck it depends on how the solenoid is rated. Some coils are momentary solenoid coils use in applications requiring high torque like shifting and if left energized would burn up. While others are used for holding or pushing but have less torque and stay energize continuously. There are many different applications of solenoid. So be careful which ones you choice and read the specs.

Don

Offline Hagar

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Re: Solenoid driven V8 - Work in progress
« Reply #23 on: October 16, 2016, 07:47:18 PM »
I think my brain was on holidays when i started to design this engine. A simple and easy to understand thing i didn't see : as four magnetic "pistons" are very closely located in each bench, they create forces pushing them on guides inside their coil. All moving parts won't... move. :disappointed:

Magnets are OK on one cylinder or V-twin solenoid engines, not on a small V8 nor in line engine.

So i'll try iron pistons.

For now, here is the crankshaft i decided to machine out of an aluminum rod. It won't be a very powerful engine and solenoids only generate forces (no hits). Aluminum should be strong enough.















Offline Hagar

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Re: Solenoid driven V8 - Work in progress
« Reply #24 on: October 19, 2016, 01:41:13 PM »
I'm testing a one coil assembly to measure force it supplies. I realize a simple iron cylinder is pushed in the middle of the coil when tension is applied. I expected it would be pulled out. :headscratch:
No matter where is plus and minus on the coil : the iron "piston" reaches the middle.

If i try now a neodymium magnet piston, it is ejected out of the coil, as it should be. And force i measure is about 50 grams, which is a very good value. High enough to make the engine turn.
But as i said, i can't use magnets on in line coil engine because of radial magnetic forces that would lock every pistons in their guides.

I've seen videos of working V8 solenoid engines. There must be a solution. But now, i've no idea... :shrug:

Those who know this kind of things, could you help me ?

Offline Admiral_dk

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Re: Solenoid driven V8 - Work in progress
« Reply #25 on: October 19, 2016, 08:54:52 PM »
No experience in this area, so I will just give you credit for a very nice crank  :praise2:

Offline Zephyrin

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Re: Solenoid driven V8 - Work in progress
« Reply #26 on: October 19, 2016, 11:34:32 PM »
A magnetic fields close to an iron piece turns the elementary magnets inside the iron, which becomes a magnet of opposed polarity; hence the attractive force whatever the polarity of the current. this orientation lasts as long as the magnetic field.

In a magnet, the orientation of all those little elementary magnets is "frozen" or permanent, therefore attractive or repelling force occurs upon energizing the coil according to the polarity of the current.   
« Last Edit: October 20, 2016, 07:24:32 AM by Zephyrin »

Offline PStechPaul

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Re: Solenoid driven V8 - Work in progress
« Reply #27 on: October 20, 2016, 01:51:37 AM »
Perhaps you can wind the solenoid with two coils, so that one will move the iron slug in one direction, and the other will cause the motion in the other direction. Both coils energized would move it to the middle. Even with a single coil, the slug could be pulled from one end to the center, and then the coil could be de-energized and the flywheel could move it to the other end of the coil. At that point the coil could be energized again to obtain a double-acting piston.

Offline Hagar

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Re: Solenoid driven V8 - Work in progress
« Reply #28 on: October 20, 2016, 11:31:10 AM »
Thanks for explanations.

I don't give up. Iron pistons had been removed and neodymium pistons take place instead. As i supposed, crankshaft motion is harder but at least, it's not locked. I think it's free enough to go on the electric V8 adventure.
I had to make different choices. In order to increase force applied to the crankshaft, no four-stroke run now, but two-stroke. So, two cylinders will "fire" together instead of one. I expected to use a 8V power supply. It'll be a 12V. Force measured increases from 45 to 70 grams per cylinder and there a 0,65Amp current flow in a coil.

Hope it's OK. Back to my workshop and let's play a little...

Offline Noitoen

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Re: Solenoid driven V8 - Work in progress
« Reply #29 on: October 21, 2016, 12:40:40 PM »
You can wind a coil around a magnet that can cancel the magnet's power when energized. In fact, this is how most of the battery powered irrigation controllers work so save power. A pulse on the coil moves the piston and it sticks to a little magnet to keep the valve open until a reverse polarity pulse cancels the magnet's attraction and releases the piston.

In a extreme case you can take advantage of this principle. It would complicate the drive but it's not impossible.

 

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