Electromagnet and Quarters

[Menicus]

Good afternoon Internet,

I have a desire to build an electromagnet using a 24V, 15A power supply. I need it to keep a Canadian quarter (the coin) in place. I have 22, 26 and 30 gauge magnet wire on a spool that fits the quarter in the center just perfectly. I also have a value pack of an assortment of resistors from 1 to 3.3m ohm. I need the magnet to hold the coin as the platform all this is sitting on is flipped upside down. All I need is for the magnet to hold the quarter against gravity, but to be able to do many, many coins, one at a time and I would rather not need to replace a battery. I know a bit about electricity, I believe I have all the parts I need but I have no idea what combination of resistors to use. This is partly due to not fully understanding the underlying physics but also because I'm not sure how much juice is needed to hold the coin.

Does anyone have any insight or knowledge they would be willing to share?

 

[CDRIVE]

Good afternoon Internet,

All I need is for the magnet to hold the quarter against gravity, but to be able to do many, many coins, one at a time and I would rather not need to replace a battery.

I really don't understand this part of your question. Also, do Canadian coins contain ferrous metal? In the old days there was no ferrous metal in U.S. coins. They were literally worth their weight in precious and semiprecious metal. None of which was ferrous. I'm sure Canadian coins followed the same conventions in the day.

Chris

 

[Menicus]

Canadian coins nowadays from pennies to quarters are 90+ % steel plated with something or other. A normal magnet attracts them. Something about cost cutting...

But more to the point, don't worry about the one at a time, imagine there is just one coin to be held in place. If I have the power supply mentioned, can I make an electromagnet out of it?

Thank you for your time,

Adam

EDIT: I googled u.s. coins and I see they are made out of a bunch of different things, canada switched to steel a while back to cut costs.

 

[CDRIVE]

Do you have any 12VDC relays hanging around? It'll save you a bunch of work. Just remove the contacts mechanism.

Chris

 

[alfa88]

Question: Does a magnet show attraction to the coin? My only experience with a Canadian 25 cent piece is annoyance (no offense intended) of them being rejected in a US coin slot.

 

[shrtrnd]

Yeah, I was wondering about the year of your Canadian coin.
Magnets only work with iron-type alloys.
I don't believe there is any steel in US coins for example, some kind of zinc alloy.
I'd make sure your quarter actually works with a conventional magnet, before I tried
building an electromagnet for it.

 

[CDRIVE]

Roger that! I just tested some U.S. coins. Under the plating they appear to be all Zinc and not magnetic. This means that his electromagnet will have to have a core material made of 100% Unobtainium!

Chris

 

[shrtrnd]

During the WWII, to save copper the US minted a steel penny, but that was it, as far
as I know. (1943 in Philadelpia, Denver, and San Francisco)

 

[CDRIVE]

Menicus, what's your backup plan? Vacuum would be a viable option. What's this for?

Chris

 

[eKretz]

Magic trick is my guess. Vacuum would only work if you could make it completely silent.