Microwave transformer electromagnet questions.. 1

[want33s]

Hi Guys, Sorry I'm a noob and know next to nothing about electromagnet theory and construction.

I am tasked with constructing a device that can be towed along a dirt road to pick up railway dog spikes (approx 115mm X 15mm X 15mm steel weighing up to 150 grams)

I have a plan in mind for microwave transformers with the secondary coil removed attached to a @1000mm square plate then the plate insulated from the trailer.

Will multiple electromagnets work attached to the same plate?
What is the ideal voltage? I see lots of YouTube vids with anything from an AA pencil battery to a 12V car battery.


Jas.

 

[BrianG]

Huh?? What is a "microwave" transformer? From your description of the job you need a regular metal detector, or several side by side (but not too close to each other) to cover a wider sweep in one go.

 

[want33s]

By "microwave transformer" I mean the transformer out of a household microwave oven.

A metal detector won't pick anything up from the ground as I need this device to do.

 

[BrianG]

Ok, language ambiguity: by "pick up" you mean literally, not meaning "detect" the presence of the spikes! In that case using a mains "transformer with the secondary coil removed" won't produce the sort of magnetic flux you would need in the large metal plate. This is because the magnetic circuit is still local to the transformer.

Transformers use 'E' and 'I' shaped soft iron interleaved laminations; you would have to separate these to fit only the E sections through the coil bobbin to get any magnetic flux outside the transformer. But all this is likely to do is attract the metal plate. Most of the flux will be contained in the plate: to produce an external field beyond the plate you need to have a gap in the plate, e.g. two smaller plates extending the transfomer laminations (think of the poles of a horse shoe magnet) I suggest you look at the electro-magnetic grab crane pickup used by auto wrecking yards!

 

[LiteYear]

Kudos to your BrianG for deciphering that. I'd written the OP off as a loony, not realising it was just an ambiguous word choice! Now it makes sense.

 

[want33s]

BrianG: I have no need for a detector. I can see the spikes on the ground. All I need to do is construct some sort of apparatus to collect them.
USA and Australia almost speak the same language, I'm surprised you didn't think I meant a pickup truck.
I thought an electromagnet setup would be easy enough but unfortunately it isn't my field of expertise.

Liteyear: Loony huh?

 

[hacksaw]

magnetic sweepers are commonly used and cheap

based on permanent magnets in side a roller, there are other designs suitable for highway cleaning

 

[VEBill]

E.g.

http://www.princessauto.com/mobile/product/productDetail.jsp?productID=8238305

"120 pounds lifting force"

One might have to find a local vendor of similar products.

 

[want33s]

VE1BLL: Thankyou for the link.
One of those sweepers looks much simpler and easier than powered magnets.

 

[Higgler]

This one's real heavy duty.

http://www.amazon.com/Heavy-Duty-Forklift-Magnet-Magnetic/dp/B00A29M1TM/ref=pd_sim_sbs_indust_3