[HomeBrew] Open core solenoid calculations help.

[hwhall at compuserve.com]

I'm not sure you've given enough data to answer the question.
1) Grams are (technically speaking) a mass measure, not force or weight. If you mean to move a mass of 20g then we'd need to know what forces are acting on the mass: such as gravity & friction. Or perhaps you meant you want to create the force equivalent of 20g and normal gravity?
2) Is the solenoid to pull horizontally or vertically or some angle in between? If vertically, gravity will be the chief force acting on the mass. If horizontal, friction may become a major factor.
3) Is the 20 grams the mass of the solenoid's moving armature only? Or is the 20 grams to be pulled in addition to the armature?
4) Is the power source to be AC or DC? If DC, you may consider making the armature a magnet. That should lower the necessary electrical power. But in any case, the armature composition (type of metal) can affect the results. Shape and size of armature will also affect the results to some degree.
5) What is the max power available from the 30 volt max supply? (Power is volts times amperes.)
6) I may be misreading your description, but it sounded like you wish the armature to remain outside the coil even when energized. That is, it sounded like you want the coil to pull the armature 2mm closer but not pull it inside the coil. If so, that's much harder (takes much more power) than pulling an armature that begins partly inside the coil a further 2mm into the coil when energized.

If you already have the armature & 24 guage wire on hand to work with, it may be faster to experiment than to try to calculate it all ahead of time. 

And I guess I should say.... if this is supposed to be a school lab experiment, we ought not give you an completed answer, unless the lab instructions include seeking consultants.

Wayne
WB4OGM
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Hi, does anyone know how to calulate the needed numbers of turns a open
core solenoid must have to be able to pull 20 grams?
It will be made on a coil form made of non metallic metal, with these
dimentions: internal diameter 7mm,solenoid turns height 25mm.
Maximum voltage 30 volts DC. Distance from the coil end to the armature
bar in a unpowered condition: 4mm
Distance to armature bar when powered: 2mm. I am thinking of using 24
AWG magnetic wire and will also like to know the amperage pull of the
coil,and  the
outer diameter of the coil. Sadly maths is not something that i am good at.

LA3RMA
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