Simple nail and wire Electromagnet problem !
So I built a simple electromagnet out of a nail and wire, I hooked it up top power and a switch. What I need to do is to lift a small metal ball the size of a common marble with my electromagnet, when I press the switch ( momentary, when you press it, it shut off power and when you release it power get back) the ball should fall of it, but problem is, the ball stay magnetized to the nail !!
The only solution I found up to now is to make the electromagnet just enough powerfull to hardly lift the ball, but I hate it because its a pain to get the ball to stick on and it often fall off randomly.
Is there a way the ball could fall off every time I press the switch without reducing the strength of my electromagnet?
Thank you !!
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One simple thing to try would be to apply a thin layer of tape to the head of the nail that contacts the ball. That would limit the weight of the object that could be held in place, but it might just be keep the ball far enough away that the residual magnetization could not keep it in place. A little "air gap" can make a big differnece when it comes to how heavy an object can be held in place.
If you are willing to change to a different type of switch, you could use a DPDT switch arrangement. In this setup, one switch position allows the full current to flow in the electromagnet, to hold the ball. The other switch position is used to turn it off and release the ball, by applying a smaller current in the reverse direction. The current in the "release" setting would be limited to a lower value than the hold current by having a resistor in series with the electromagnet. This would let enough current flow to canel out the magnetization and release the ball.
If you are willing to change to a different type of switch, you could use a DPDT switch arrangement. In this setup, one switch position allows the full current to flow in the electromagnet, to hold the ball. The other switch position is used to turn it off and release the ball, by applying a smaller current in the reverse direction. The current in the "release" setting would be limited to a lower value than the hold current by having a resistor in series with the electromagnet. This would let enough current flow to canel out the magnetization and release the ball.
Mar 7, 2011. 2:35 PMPatented (author)
says:
Too bad the school power supply has a shortcut protection so making an electromagnet with that source wont work ! But I tried with the same iron nail and same wire but with 2 ''D batteries'' and it work just fine, when the switch is pressed the ball immediately fall off
Mar 6, 2011. 7:35 PMPatented (author)
says:
Your idea of a DPDT setup seems pretty promising ! I will check around to find some sort of a plan to make this setup , thanks for the idea !
I tried some tape on my ball and I did a pretty good difference ! Tommorow at school we have good power supply, I will try to find a good inbetween Voltage to make it work as I want. I will get back with some news !
Thanks a lot man !
I tried some tape on my ball and I did a pretty good difference ! Tommorow at school we have good power supply, I will try to find a good inbetween Voltage to make it work as I want. I will get back with some news !
Thanks a lot man !
Mar 6, 2011. 7:17 PM7654321
says:
Some metals stay magnetic after they've been magnetized. Try a different object besides a nail, which is "hard" magnetic. Get one that is "soft" magnetic.
Mar 6, 2011. 7:30 PMPatented (author)
says:
Thanks for your answer, do you have an example of a soft magnetic ?
Mar 7, 2011. 6:06 PM7654321
says:
Oh, well I trusted Instructables :( http://www.instructables.com/answers/Does-an-inductor-start-with-a-magnetic-field-or-d/
Apart from Sean's answers., there is quite a lot of misinformation in that answer.
Steels,because they contain carbon, have a sufficiently asymmetric structure that they will become permanent magnets.
Steve
Steels,because they contain carbon, have a sufficiently asymmetric structure that they will become permanent magnets.
Steve
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