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Nichrome wire heat up Answered

Trying to heat up 2 pieces of nichrome wire in a series. Both loops tested and work by themselves. Only when combined in a series it blows. Is their a rule idk that nichrome wire can’t work in a series??? Thanks for your council in advance

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Cumberson
Cumberson

1 year ago

I think I get what both of you are saying. Y’all saying it way more technical then I can. I’ve never had any formal training. In fact, all I’ve taken is the electronics class here on instructables. So yeah, it’s hard to grasp. But I think I get it.
I bought a couple of toasters and clipped the cords. The voltage in drawing is 120 from the plugs. The pieces of nichrome is 25 feet long. I want to split it a 3rd time for 3 25 foot long pieces of nichrome wire. The plugs are polarized. The “blow’ is a power surge protector I’m deliberately using so it can blow. Better then going all the way downstairs to the box. 2 fire extinguishers by my side for every test. I burned my hardwood floors quite nastily already. So I raised the wires in the air. Looks like power lines now. I’m currently using 20 gauge nichrome. Might knock that down to 26 or 34 gauge. When I took apart my soldering iron, they use thread skinny nichrome to heat that up. Like 88 gauge. Shocked how thin it was. Anyone know where to buy that skinny of nichrome wire ???
Any other advice is appreciated
The foil tape on one of the wires was an attempt to heat that up. I want to heat 25 feet long by 1 foot wide. That’s it my real goal here. That’s why 3 cords to heat up. So I get about a foot wide. So I tried the foil tape. Maybe I could do 1 circuit, foil heat up to make foot wide. Shockingly, this failed massively. The tape disbursed the heat. The rest of the wire not covered got super hot. The tape covered area (about half) didn’t heat up at all. Stayed room temp. No idea why that happened. Test 93 failed horribly.
So any other ideas or help is appreciated

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Orngrimm
Orngrimm

1 year ago

"It blows" can 2 meanings here, please specify:
- It blows, it sucks, it is shit, it doesnt work, it is subpar to what i expected
- It blows UP, It explodes, burns the wire thru, it has a much too high energy
I suspect the first as dictated by physics.

See, lets assume, each loop of Nichrome has 1Ohm and you are feeding 5V.
With one loop: P=V^2/R = 5^2/1= 25/1 = 25W which is a respectable power and may indeed show the nichrome glowing.

Now, with 2 loops in series:
P=V^2/Rtotal = 5^2/1+1 = 25/2 = 12.5W
You may think, this is not so bad... But wait: this half power is now on 2 times the lengt of wire, so each wire only dissipates 6.25W. Thats only 25% of what it did with only one loop.

So given a constant voltage (Most likely) you will get 1/4 of the power on each wire if you double the wires and put them in series.
And 6W will propably get the wire warm/hot but i dont think it will get it glowing if the wire didnt burn thru with 25W before...

Edit: I see, jack was faster with the same explanation basically. Good at least we 2 think the same. :)

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Jack A Lopez
Jack A Lopez

1 year ago

I would expect it to work the other way.

I mean, if you are driving them from a voltage source, V, and each piece has resistance R.

In series, the total resistance is 2*R, and only half as much current, I = V/(2*R). The total dissipated power is half what it was, and that power is divided between two pieces. So the power dissipation, per lump of wire, is one quarter the full amount, (1/4)*(V^2/R), where the (V^2/R) is the power I expect for one length of wire, R, connected by itself, across the same voltage source V.

You know what I mean? I expect expect those two pieces of wire would be much colder, not hotter, when connected in series.