Where to buy electromagnet

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#1
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Any quick advises for online stores that sell electromagnet in Canada (or US)?
I need a small and light electromagnet capable of lifting reliably a 9V battery (force of 1-2 pounds should be good with a large safety margin).
Thanks!

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Find a relay and remove the armature. Instant electromagnet. Not strong enough? Get a bigger relay.

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Do all 9V batteries have a steel case? I do not know, but I like to be cautious about such things.

Does the electromagnet have to lift from any distance or is this the contact lifting weight?

I hope you are not powering the electromagnet from the 9V battery!

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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Look for a magnetic door latch. Lots of em in New York where all the neighbors are Real Friendly. You cant pull the door away from that booger when its on.

Imagecraft compiler user

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That 'BOOGER' if its the one I have used quite often weighs a ton(figureative, not literal) and uses either 12vdc or 24vdc. You are correct though. Damn hard to pull the strike plate off it when they come in contact. But a 9v battery is easy to pull off the magnet though.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

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Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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Magnetic field is N turns x I amps. The weight is all the N turns of copper.

Imagecraft compiler user

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@BOB,
Ok, how many turns you figure is in this?

http://www.securitron.com/en/sit...

Shipping weight is 11 pounds, When I picked it up I would guess it weighs about 9 - 9.5 pounds.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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12V/.25A is 48 ohms. 1200 lbs (545Kg) of force is N turns X .25A. Must be a table that says how many feet 9 lbs of number 28 wire is, and what the length of what size wire would be 48 ohms. I cant figure it out though.

Imagecraft compiler user

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Bob,
I was SORT of kidding when I asked. Although I would not have been surprised if you had come up with a number. ;)

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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The relay idea seems to be interesting, since many stores sell relays, as opposed to electromagnets. My most important criterion here is weight, it should be about 50 grams or less. I've tried a relay I had at home (RIP relay), but it was borderline strong enough, so I need something more powerful. Unfortunately, there is no direct correlation between the size of the relay and the power of the magnet used. The one I've got also seems to have quite some shitty armature, so you get quite a poor force for the power consumed.

PS: Technically, N x I is magnetic field strength, as opposed to the actual magnetic field, which is influenced tremendously by the material used. ;). This is why even a small gap between the magnet and the ferrous object can reduce the magnetic force ten-fold and why the door latches are so poor for keeping a 9v battery in place.

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Surely there must still be some remnants of transformer manufacture in Your world.
Talk to the local transformer manufacturer.
They ought to be able to advise just how much flux at a given cross sectional area You require to pick up the load and recommend one of their standard E cores.

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For something as small as a 9v battery you could also consider a succion cup and a vaccum pump, with some tubing...

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... or Blu-Tack on the end of a stick :lol:

Ross McKenzie ValuSoft Melbourne Australia

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valusoft wrote:
... or Blu-Tack on the end of a stick :lol:

I could as well coat it with honey and unleash an army of ants.

@sbennett: I saw similar results during my search. I was surprised not to see them retailed at any general electronics/robot/hobby stores. That said, all I could find was either too heavy/too powerful or unduly overpriced.

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Go to Your local tattoo supply shop and purchase a coil for a tattoo gun from them.

More than enough grunt to pick up a 9 V battery.

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For those that are curious:
http://www.rfcafe.com/references...

#28 awg copper wire weighs 0.4837 lbs/1000 feet, and has a resistance of 70.8 ohms/1000 feet @ 25 degrees C

48 ohms resistance works out to 678 feet of wire. How many turns this is would depend on the size of the magnetic core it's wrapped around.