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So, I got some vintage train transformers, all are putting out 18V or more. I wired my frames and then tried to use them to embed the wire.
No luck. The wire doesnt even get warm. I left them clipped on there for 5 minutes. No dice. How are you guys using train transformers to embed wire? There is current passing through the wire, but its not enough to warm it up. Ended up just using a spur embedder for the first one.
Kind of disappointed because I read that these would work. :(
Whats the amp output rating on the terminals you are trying to use?
And second, after you have hooked up the wire you are trying to heat, what is the voltage measurement between the two terminals that you are using?
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I insert each wire from the transformer into the brass eyelets on opposite ends takes 2 seconds or less per wire.
I used a train transformer for years. It would be better to make direct contact with the wire. There is resistance between the eyelets and wire. It will not make your wires last long with the induced galvanic corrosion either.
Are you heating just one segment or the entire strand? The shorter the wire the greater the current and heat. E=IR.
Ill have to measure the voltage again. I made an embedding tool, between the two end contacts, its a solid 18V. The transformer is a 17.5V, 6VA transformer, on the AC side. It takes about 15 second to really head it up and get it embedded. I am heating one segment at a time. The tool is the functional equivalent of what you buy from Dadant.
Between the wires, when its hooked up, I can only get .7V across it. Its standard wire, standard train transformer, and a medium frame. Not sure how it could be any different that what you guys are using. Ive tried it with several train transformers.
> It takes about 15 second to really head it up and get it embedded.
In post #1 you said it didn't work at all, so I assume that problem has been resolved, and now the issue is that it takes 15 seconds per wire?
> 6VA transformer
The Dadant transformer said it was 2 amps. 2 amps at 12 volts is 24VA, so I'm not surprised your current process is slower. Make sure you are not using "thin" wire from the transformer to your tool, as you want as low a loss as possible there. If you want faster cycle time you will need to supply more amps.
Not sure what the issue was before, but I bought a 'lot' of transformers for 10 bucks, so I have about 7 to play with. One of them definately has an internal 'short circuit' protection. I can hear it click 'off' after a couple of seconds, then back on, and the voltage drops to 0...so that was probably the original issue. That was with juct alligator clips. I then built a proper embedding tool and tried a few more transformers. It takes a while to get it warm enough to embed, but I guess its not the worst thing in the world to be able to watch it embed and have it under controlled conditions. I DO have another transformer I found that is 18VAC 2200mA...so that would be 39.6VA right? Ive not had a regular transformer stand up to dead shorts like this...not sure this one would handle it either.Quote:
Originally Posted by Rader Sidetrack
Ill try another transformer I have and see if it speeds up the process.
Modern power supplies that are encased in plastic, for example a laptop power supply, are typically not simple transformers. They are switching power supplies, and may not behave the same way as a real transformer.
For your purposes, the best choice is a very basic transformer, perhaps where you can see the steel core to verify it is indeed a transformer. If its inside molded plastic and been repurposed from some other application, you don't really know whats under the plastic.
A 24V sprinkler controller transformer heats wires in 1/2 a second. Call local landscapers who might have old ones laying around.
If it has an AC output it is most likely a transformer. If it has a DC output it will be either a linear or switching power supply. Virtually all switching and many linear supplies will collapse if shorted. Look for a Class 2 transformer. These are designed so that they won't burn up even with a direct short. The heavier the wire the greater the current required to heat it up. If the wire is 20 or 22AWG it likely won't heat up at all with just 1A or 2A flowing through.
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This is the transformer I have but have not tried. Think it'll short and burn up?
http://www.ebay.com/itm/GTO-RB570-CL...30761805596%26
Tested this transformer out last night. I did a few frames with it. It takes about three half-second pulses to embed with it. I tested it on the wire before putting wax in it and burned a zigzag on my form board. Let's hope this transformer holds up. ***knock on wood***
If you want to slow down the heating process, you could experiment with putting a 12 volt bulb in series with the wire you are embedding. An automobile dual filament stop/tail bulb is where I'd start. Try the tailight filament first.
You will need to turn up the speed which is the amp on those to embed correctly.