MTFCA Forum

So, I have this magnet recharger on its way.
https://www.ebay.com/itm/235633745415
Besides adding a switch which is easy enough, where would I put a meter? Does it matter which leg it would go on between the switch and coils?
Sorry about having to use the full listing from eBay, could not get just a single image to load properly.
I had gotten more information from the seller that was not in the listing;
I have not powered it. It only has two thin 16ga wires coming from it. The coils are 4” in diameter by 4.5” tall. It weight 36 pounds.
I didn't pay the listing price, got it for about the cost of materials to build one.

I agree with Steve about the price. I charged my magnets with about a dollars worth of material and had great success.

An ammeter is really not needed to use your magnetizer. The unknown is how much voltage is needed charge a magnet. I would start with a 12 volt battery and add more batteries in series if needed.

Good luck with the remaining assembly.

Art Mirtes

Using the David Gingery plans, the copper wire alone would/could be in the ballpark of $250 plus other material cost. Plus, I really didn't want to spend that many hours winding the coils. I have the power supply following the plans in the book that I will be using.
As I said, I did not pay the asking price ($400 with shipping) and considering what the ones in this size are going for, think I got a decent deal.

You can place an ammeter in series with the circuit on either side to measure the current draw.

jsaylor wrote: ↑

Wed Dec 11, 2024 12:18 pm

You can place an ammeter in series with the circuit on either side to measure the current draw.

Thank you!

Well,l got some good news this morning! The seller refunded part of the shipping cost, to the tune of $56. I am a happy camper!

That's good to hear. It shows that there are a lot of good and honest people in this great hobby.

Arr Mirtes

I’m a bit surprised an old car fellow like you sprang for that unit at that price Mark!

LOL! This old car fellow didn't want to hand wrap 12 pounds of No 18 wire! Besides I wanted one to charge other magnets, not just T.

Mark, I get it exactly why you bought instead of made. Sometimes a fellar can save money by doing a paying job instead of building something but having more time in it. I often find myself debating whether we spend the time to fabricate or outsource it and pay someone else while we work on customer's projects.

Seeing above someone comment their test weight was 7 pounds. My test weight is only 4 pounds. Is mine too light??

Is mine too light??
No clue, I was just going by the material list in David J Gingery's book. Number of guys just use a few wraps of house wire and seems to work for them. Just wanted something a "bit" more than the latter. There is the whole thing about ampere turns and wire gauge that outside my box.
In the meantime, babbitt to pour and bore, KR Wilson generator test stand to rewire..the list goes on.

To go back to your original question - I would not use a traditional switch but rather a pushbutton type switch as you would only need a short burst and not a constant flow of current. That way a ampmeter does not really gives any useful information. This way your magnetizer does not get to hot either. 3 pushes on the button and you should be good to go.

Got the charger, no photos yet, but looks well-constructed. Tried it with a battery charger on 12 volts, ya it's going to need more power than that.

I would try it on the lowest DC setting on my welder but no place to plug it in right now.  
RE the push button, got one that should be more than adequate for the job.
So, need to revamp the Gingery power supply I built before and give it a good work out.