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switching power supply fix

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nickpatsos

New Member
Hello there!
I bought a switching power supply (MODEL: MW7H380GTGS, PRI: 100V - 240 V ~60/50Hz 700 mA.

It has a hole at the side that you can insert some kind of resistance so you can regulate the voltage and the current.

I want to use it to supply a circuit on breadboard

As i do with other power supplies, i cut the wire at a point. I remove the plastic and then i wind the power supply's cables with small wires (the ones which use for connections on breadboard). But when i remove the plastic from this one, i saw that the positive's wire consists of lots of small red wires and the negative consists of gold ones. I try to wind them but nothing happens.
Someone told me that these wires have vernis and i have to remove it somehow and then try to connect the wires.

Any suggestions to fix it?(i am a novice so be gentle!! :))
P.S. If i cannot connect to the breadboard wires can you suggest a way to reconnect the wires of the supply?

Thank you!
 

nickpatsos

New Member
Here is a photo of my supply. At the right, the power supply shows up.
At the left is the wire of the supply that i have cut off. I want there to connect the wires we use for connections on breadboard.
 

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Sceadwian

Banned
You mean veneer? That look like litz wire. That's an extremely nice power supply! What you're looking at is a bundle of magnet wire, meaning it has a thin enamel coating over the top of each wire, running all of these lines in parallel is better at high currents. To get rid of the enamel the best way I've found is to generally pass it through a small gas flame, you'll get a little smoke as the enamel burns off (I wouldn't recommend breathing it) You'll have to clean the smut that's left off afterward very well and solder the jumper wires onto it, twisting it will not produce a reliable connection. It seems a little strange to have this type of wire on a small supply, what is the voltage and current the output is rated for?
 
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peterb2

New Member
I'll agree Sceadwian here too about removing the enameling on the conductors. I tend to just burn through the stuff with the soldering iron, flowing on plenty of fresh clean solder (an it's rosin) to tin the end. It will smoke a bit and smell but yes, try not to breathe it!.

One final thing about using Switchmodes like this for breadboard. Make sure the power supply unit has plenty of real issolation from Mains so that if any kind of failure happened as you worked with the circuit design on your breadboard there's no chance you can ever become bodily connected to Mains voltage potential.
 

Sceadwian

Banned
That power supply likley can suplpy a decent ammount of current, there's no other reason I can think for them to use Litz Wire, so you'll almost certainly want to design an overcurrent protection, at the VERY least you'll want a 1 or 2 amp fast blow fuse. Most breadboards are only good for about 1 amp because of the contact design.
 

peterb2

New Member
Only experience i have found for Litz style conductors such as in this cable to be used is if the cable is in a situation where it is going to be moved often as in being coiled/uncoiled many times it its life or it needs to be draped out of the way easily. I've seen it used often on PC Notebook chargers and the like and a lot of headphones as in portable listening devices ie iPod etc....
 

Sceadwian

Banned
That's not litz wire peter. That's just highly stranded cable, what he has each individual strand is insulated.
 

peterb2

New Member
That's not litz wire peter. That's just highly stranded cable, what he has each individual strand is insulated.

Agreed and why i called it Litz Style.... The real stuff is so fine a strand guage and makeup it's more like fur than a wire all bound up by some kind of outer insulation sleeve which on really early RF parts (coils etc) tended to be silk. :)
 

Sceadwian

Banned
You've re-iterated the point that I was contesting =) Litz wire is not made by it being a fine grain wire structure, it's made by the fact that each wire is insulated from the others. If it's not insulated, if it's just air tight fine wire, it's not litz.
 
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peterb2

New Member
You've re-iterated the point that I was contesting =) Litz wire is not made by it being a fine grain wire structure, it's made by the fact that each wire is insulated from the others. If it's not insulated, if it's just air tight fine wire, it's not litz.

Yeah ok... semantics but agreed yes (as example) the stuff used in old time RF coils that was outer-coating covered with a silk thread had each strand insulated usually in some kind of enameling. Just made an assumption in my description before, sorry about that.... :)

Anyone interested do a Google (images) and you'll see plenty of examples of the stuff some of which can look quite beautiful in an engineering way!

Here's a good closeup"

https://img.alibaba.com/photo/105308890/Noah_Technologies_Litz_wire.jpg
 
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