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How do I properly power my electromagnet?

I just purchased an electromagnet from Amazon for a small prop for an upcoming play I am directing. Now my problem is... I do not have a clue as to how to supply the power to it. It needs to be able to run steady for roughly 3 hours.  What size batteries would I need -the smaller the better in terms of size since the prop itself is not that large,  ut will do whatever is necessary to function properly.


Here is the only information the electromagnet had attached to it:

'Feature:
Electric lifting magnet
Powerful and compact
Smooth and flat surface
Low consumption and reliable
Applications: assembly line, sorting machine, mechanical arm, experimental facility, etc

Specification:Material: Metal
Input Voltage: 12V DC
Lifting Force :20N
Overall Size : 15 x 15 mm /0.6 x 0.6 inch(Dia. *T)
Thread DIA : 3mm
Lead Length : 24cm/9. 5 inch"

Any help would be greatly appreciated. Thank you in advanced!

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Jack A Lopez3 months ago

Why not design your mechanism so that it only uses power when releasing the thing to be dropped, instead of doing things the backwards opposite way?

I mean it would probably use a lot less energy that way, so you would not need large batteries to power it.

DeanB77 (author)  Jack A Lopez3 months ago

That would be an excellent way of doing it; I am just not sure I would have any clue how to do it that way. If you have the time to explain a general concept, please feel free because it would be extremely appreciated. To explain the concept on my end -it is for the play Beauty and the Beast and needs to release petals from the rose. Would be excellent if it was able to do that a few times to draw out the effect. Thanks ahead of time!

Well, so far I have thought of approximately three different mechanisms for this disintegrating rose.

The first idea is just a permanent magnet, surrounded by a thin shell, with a way to move the magnet's position relative to the shell.

If you have seen a gizmo called, "quick release magnetic pickup tool", then you already know how this thing works. It is kind of like an electromagnet, but without the need for electricity. The field near that thin shell surface is changed from strong to weak just by moving the magnet inside from near-touching, to a few centimeters away from that surface. A picture of one of these things is attached.

The second idea is to grip a bunch of flat petals in between two flat jaws that move together, and squeeze whatever is in between them. Sort of the closest existing thing that I think exemplifies this mechanism, is this thing I think is called, "electrical hook clip". A picture of this is attached. The feature that is special about this mechanism is the thing that pulls the jaws together, is long and skinny. In the rose version of this, the long skinny part would be the stem of the rose. Moreover the gripping jaws are on top of the stem, where they need to be to grip the petals.

The third idea I got from reading what Downunder35m wrote regarding "some string or wire that the motor pulls out of the petals and their mounts to make them fall one by one". I do not have a easy picture for this one, but I am imagining loops of strong thread, running through holes in a stack of plastic rose petals, with a separate loop of thread on top to sort of pin the stack in place. Pulling the top loop of thread free would dump the stack.

Moreover, I can almost imagine several stacks of petals, all pinned in place by multiple loops of the same thread. Although I am not sure if just pulling on that thread would dump each stack sequentially, or like what exactly would happen, just from pulling on that one thread. I mean, it might also just jam, and not pull itself apart, and not work at all.

magnet-in-a-box--magnetic-pickup-tool.jpgelectrical-hook-clip.jpg

Did you ever consider a geared motor?
Would run quite slow and you could use some string or wire that the motor pulls out of the petals and their mounts to make them fall one by one....
And it would only require a fraction of the power your magnet would need.
With a small enough motor 2 or 3 AA batteries will do.....

Yeah. That would be a neat trick. I mean if you could unravel the whole thing like a sweater, just by pulling one string.

DeanB77 (author)  Downunder35m3 months ago

Hm, this could be an option also... just need to figure out what the mount would look like.

If I follow what you have said so far, you want a rose, or rather something that kind of looks like a rose from far away, that can disintegrate on command, quickly or slowly, into loose petals, and maybe an empty stem.

Is there an actor holding the rose while it disintegrates?

Or does the rose just disintegrate on its own, like sitting in a vase on a table, without anyone touching it?

DeanB77 (author)  Jack A Lopez3 months ago

it is under a glass dome by itself

steveastrouk3 months ago

Set your load up and measure the voltage you need to keep it on, measure the temperature too. Make sure it doesn't overheat at 100% duty.

Downunder35m3 months ago

Hard to say apart from requiring 12V.
These things are often used to keep doors open but not all are rated for 100% duty cycles.
It also depends what material you hold with it, not all steel is the same here.
You need to do some tests if there is no datasheet available.
Connect to 12V and see how moch power it draws.
Add a metal plate or whatever you need to hold and check the difference in power consumption.
Let run for a while and keep an eye on the temperature to makuse sure the magnet won't overheat in your three hours.
You might get away with a 12V, sealed lead acid battery if the magnet is still strong enough once the battery voltage starts dropping.
Otherwise 2 batteries and a 12V regulator of sorts.

DeanB77 (author)  Downunder35m3 months ago

Awesome, thanks for the info! It will not be holding too much -just some rose petals with small pieces of metal to hold them on.

+1

DeanB77 (author) 3 months ago

Here are pictures of the device.

IMG_1637.PNGIMG_1636.PNG