Most efficient way to make a strong solenoid.

[RichardHole]

Hello

How practical would it be to make a solenoid or a number of solenoids parallel to one another that would pull a weight of about 3kg over a distance of 160mm? Leverage could be used if needed. I am wondering roughly how many amps and what length of copper wire would be needed if 12 volts is used and also what they would be for 24 or 240 volts. If 12 volts is used, the current may have to be very high and possibly too high for a computer power supply that is limited to about 10 amps. I thought the solenoid to open the screen door if it is easier to do than using a motor.

It would be good if I could find some info on what is the most efficient way to build the solenoid regarding the minimum amount of wire needed and the lowest power and heat produced. I think the best way to make one would be to wrap some very thin aluminium leaf or shim brass around a steel rod and wind the wire around that and then pull the rod out and use the next size rod down for the pin or roll some paper between the rod and shim metal to use the existing rod.

The variables would be the diameter of the rod, the thickness of the wire (I have about 0.5mm copper), the number of layers of wire above one another, the length of the wire and the length of the solenoid and rod. It may be more efficient to use a number of fairly small diameter solenoids with only one or two layers of wire to keep the wire as close to the steel rod as possible. A higher voltage may be more efficient or even 240 volts could be used. A number of solenoids could be put parallel to one another with the pins connected so the combined force could pull what is needed.

What do you think is the most efficient way to make a solenoid regarding the above variables?

I am also trying to establish a number of nonprofit projects and free groups to help many communities. I have a number of separate websites with rare information, new ideas, solutions and inventions to help many people at

http://www.truesolutions.info

. Any help and feedback regarding these would be appreciated. I am seeking people to help promote these and I can send you letters or social media messages to share.

Your help would be appreciated
Regards Richard.

 

[MikeHalloran]

Any number of thick "Electrical Engineers Handbook" type volumes will have a fairly complete set of equations and parameters for designing solenoids. Radial clearance between armature and coil does not have a major effect. All of the possible parameters conflict with each other to some extent, so a successful design is a compromise. Your definition of 'efficiency' is rather fluid, and not defined well enough to use as an optimization function.

You could perhaps learn a bit by putting the requisite set of equations in Mathcad or Excel and beating on the problem for a week or two to get a feel for the parametric interactions.

You will eventually learn that because of their inherently nonlinear force/stroke curve, solenoids are not a good choice if you need ~3kg of force over the entirety of a 160mm stroke. Four bar linkages may help some, at some expense in complexity and durability, but you are really in motor or linear actuator territory.




Mike Halloran
Pembroke Pines, FL, USA

 

[IRstuff]

3kg over 160mm against gravity requires 4.7J. Speed then provides the minimum power against gravity. If you are moving it laterally, then the question requires knowing what friction is involved.

TTFN
I can do absolutely anything. I'm an expert!
faq731-376 forum1529

 

[EdStainless]

Take Mike's advice and look at linkages with motor drives and forget about using solenoids.

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P.E. Metallurgy, Plymouth Tube

 

[dgallup]

Not practical. Distance is the enemy of magnetic attraction. While you can easily make a solenoid that will lift 3 kg with essentially no air gap, the same solenoid will create essentially no force with a 160 mm air gap. As noted above, many other much better solutions.

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[RichardHole]

Hi

Thanks for the replies. Do you know of any simple low cost systems that are already for sale that could do what I need? It would be good if I could just buy the motor and system to release or unwind it when the power is off.

Regards Richard.