Making a glow plug? or hot metal wire..

[Boncuk]

Google nichrome wire. You can get almost any resistance you want. I bought some about the size of 28 gage that has a resistance of about 7 ohms per foot. I hook about a foot of it stretched tight to 12 volts and use it to cut foam. Works like a champ.

You should try out the high G-string of a guitar. Works like a charm.

 

[Ian Rogers]

Am I missing a point here?

How will you make a 2A rated wire to carry 10A other than increasing the supply voltage by the factor of 5.

I think so... If you place a 2 amp wire across a battery (12v 200a) the wire will melt.... burn away... turn to carbon... IF you limit the current to 2 amp it wont!! so there has to be an excess current to burn it away..... THIS is the point I was making...

You are assuming that a 2 amp rated wire can only carry 2 amp. I believe it will carry a great deal more as its heating up and turning to dust.

 

[Boncuk]

I think so... If you place a 2 amp wire across a battery (12v 200a) the wire will melt.... burn away... turn to carbon... IF you limit the current to 2 amp it wont!! so there has to be an excess current to burn it away..... THIS is the point I was making...

You are assuming that a 2 amp rated wire can only carry 2 amp. I believe it will carry a great deal more as its heating up and turning to dust.

I didn't miss the point while you missed it thoroughly.

A 2A rated wire connected to a voltage source of 12V will have a resistance of R=V/I, R=12/2, R=5Ohm. The rating does not only apply to the current, but also to the supply voltage. That's why heating wires are normally rated in Watt. The battery capacity has nothing to do with the actual current flow.

Another example: Car interior lights are normally rated 2W. So the current flow will be I=P/V, I=2/12, I=0.1667A. Calculating for the resistance Ohm's law is applied: R=V/I, R=12/0.1667 R=71.99Ohm

You are certainly not trying to tell me that 199.883A of excessive current have to be burnt away, are you?

(BTW, the max possible discharge current of a battery does not imply that the rating is 200Ah as your post suggests. The max discharge current depends on a lot of different factors which I won't mention here.)

Most wires have a positive temperature coefficient. There are some exceptions, e.g. uraniumdioxyde having a negative temperature coefficient.

A positive temperature coefficient means increasing resistance with increasing temperature, hence decreasing current.

Just think about that, too.

I hate to repeat myself, but I'll make an exception today. Believe is a matter of religion. Electrics and electronics are a matter of science.

Boncuk

 

[Ian Rogers]

A piece of wire is a piece of wire... the rating is given to the wire for a safe working load.....If you place a 21watt bulb in a circuit... Then connect with wire RATED at 50mA..... the wire WILL burn... the bulb WILL illuminate briefly.... This means that the RATED wire has been exceeded and has blown to bits. (12v 1.75 amps)

What point am I missing exactly!!!! All i was saying is a miniscule wire across a battery (whatever size) will take more that its safe current rating when it burns up.

The size of the battery was irrelevant.....

Please don't think I'm dumb in electronics....I've been doing this for some years now... throwing different specifications at me, wont impress.

I really think you missread my orignial answer.....

 

[Cazzo]

Ok guys so i notice alot of helpful talk about the battery and how it may explode, and the types of think wire that will glow. e.g nichrome, guitar string, bulb filament etc.

And so basically, to test the wire i choose, to experiment with it. what sort of power am i using??? your saying batteries. why not an AA like the link says? im trying to understand how much current i can get from a battery (as current heats the wire, not voltage) and how i can boost the current.

I was looking at homemade welders, and how the transformers welders use are wired to provide low voltage, and high current...as the current is the heat.

another question, when you say "privide 70 amps" to me 70 amps sounds like a crazy and dangerous amount. like... i have 30A 240V mains voltage, and im aware that 1A can kill you...

So how do batteries put out 70A, and why dont you die when you touch the terminals??? same as car batteries, hundreds of amps available, but no death when you touch terminals.

Can someone please explain all this to me if you can, because i have always wanted to know..

 

[Cazzo]

BTW, who helped you to choose the nick? Gregorio De Falco?

Hahah not Gregorio De Falco "damn it" i mean the other hahahah lol interpretation of, Cazzo

 

[Boncuk]

A piece of wire is a piece of wire... the rating is given to the wire for a safe working load.....If you place a 21watt bulb in a circuit... Then connect with wire RATED at 50mA..... the wire WILL burn... the bulb WILL illuminate briefly.... This means that the RATED wire has been exceeded and has blown to bits. (12v 1.75 amps)

What point am I missing exactly!!!! All i was saying is a miniscule wire across a battery (whatever size) will take more that its safe current rating when it burns up.

The size of the battery was irrelevant.....

Please don't think I'm dumb in electronics....I've been doing this for some years now... throwing different specifications at me, wont impress.

I really think you missread my orignial answer.....

I guess the problem is over your head. A piece of wire might seem a piece of wire if you look at it like a connecting element.

In a heater circuit that "piece of wire" has a different job to do.

Sorry, but I guess it's better for you to study Ohm's law again.

Boncuk

 

[Reloadron]

Ok guys so i notice alot of helpful talk about the battery and how it may explode, and the types of think wire that will glow. e.g nichrome, guitar string, bulb filament etc.

And so basically, to test the wire i choose, to experiment with it. what sort of power am i using??? your saying batteries. why not an AA like the link says? im trying to understand how much current i can get from a battery (as current heats the wire, not voltage) and how i can boost the current.

I was looking at homemade welders, and how the transformers welders use are wired to provide low voltage, and high current...as the current is the heat.

another question, when you say "privide 70 amps" to me 70 amps sounds like a crazy and dangerous amount. like... i have 30A 240V mains voltage, and im aware that 1A can kill you...

So how do batteries put out 70A, and why dont you die when you touch the terminals??? same as car batteries, hundreds of amps available, but no death when you touch terminals.

Can someone please explain all this to me if you can, because i have always wanted to know..

OK, on a side note. Yes, a 12 volt automotive battery for example can deliver hundreds of amps of current. That merely means the current is available. If I place a small few watt automotive lamp across the battery the lamp will only draw the required current to do its job. While I am not familiar with your residential home power if for example you have your mains at your home they may be 100 amp 220 volt mains service. However, if you turn on a 100 watt lamp the lamp lights and only draws about .5 amp (a half amp) even though 100 amp service is available. The load will only draw its rated current at a rated voltage (assuming it is available). Obviously if you try to place a 200 amp load on a 100 amp service things won't work and circuit breakers will trip.

As to your little project it becomes some trial and error. Matters not if you use Nichrome Wire, Tungsten Wire or whatever as a heating element. Those cute little vaporizing units are designed to output a specific heat. Too much heat and your stash is toast, not enough heat and no smoke to toke. During the trial and error it is unwise to inhale because you will likely get stoned and forget what you were doing. Then likely be found raiding the refrigerator.

Just My Take
Ron

 

[Boncuk]

A piece of wire is a piece of wire... the rating is given to the wire for a safe working load.....If you place a 21watt bulb in a circuit... Then connect with wire RATED at 50mA..... the wire WILL burn... the bulb WILL illuminate briefly.... This means that the RATED wire has been exceeded and has blown to bits. (12v 1.75 amps)

What point am I missing exactly!!!! All i was saying is a miniscule wire across a battery (whatever size) will take more that its safe current rating when it burns up.

The size of the battery was irrelevant.....

Please don't think I'm dumb in electronics....I've been doing this for some years now... throwing different specifications at me, wont impress.

I really think you missread my orignial answer.....

I'm impressed by your reply. You obviously did misread the original question of this thread.

Remember the thread was not started to find out the appropriate wire cross section for any load connected, but to know what kind of wire has to be used for a heater with the wire itself being the only power consuming element in the setup.

Again, that wire is not meant to connect any power consuming device to a power source! It's meant to produce heat without going up in flames.

Your kitchen toaster is such a device. The wires leading to the toaster must be designed not to produce any heat (or little) while the toaster is designed to turn your bread deep black when left unattended.

That's all about this thread. Why would someone use a glow plug to feed power into another device?

Boncuk

 

[Cazzo]

HAAHHAAH reloadaron understands whats goin on

Also, thanks for the explination bout stuff.

im not makin this project to heat my herb... i have another way of doin that but thats a different forum

that was just an example of battery and wire.

 

[Ian Rogers]

Nobody was talking about a heater wire........... I never mentioned a series resistance wire..... the wire HAS NO RESISTANCE (maybe about .2 ohms per foot)....... There IS NO ohms law... 12 v / 0.... Nada.... nothing.....

 

[DerStrom8]

Nobody was talking about a heater wire........... I never mentioned a series resistance wire..... the wire HAS NO RESISTANCE (maybe about .2 ohms per foot)....... There IS NO ohms law... 12 v / 0.... Nada.... nothing.....

That was the mistake I made. I was just chatting with Boncuk earlier. I thought he was talking about a regular wire that has a 2 amp rating. He was talking about heater wire, which when rated for 2 amps means it will limit the current to 2 amps (hence the resistance can be calculated using Ohm's Law).

I misunderstood him too, at first, but now I think we're all on the first page.

 

[Ian Rogers]

Hi DS

Yes I think Boncuk assumed I was talking about heating elements..... but the original post wanted to know what would happen if he shorted out a battery with "a piece of wire"....

 

[DerStrom8]

Hi DS

Yes I think Boncuk assumed I was talking about heating elements..... but the original post wanted to know what would happen if he shorted out a battery with "a piece of wire"....

Yes, exactly. That is what confused me too. Some people mentioned using heater wire instead of just a "regular" wire, which is why Hans started talking about heater wire.

At least we all know where we stand now

Regards

 

[atferrari]

Sure

Hahah not Gregorio De Falco "damn it" i mean the other hahahah lol interpretation of, Cazzo

Yes, that is why...

 

[atferrari]

I didn't miss the point while you missed it thoroughly.

A 2A rated wire connected to a voltage source of 12V will have a resistance of R=V/I, R=12/2, R=5Ohm.


Boncuk

I cannot see where that 50 comes from.

 

[DerStrom8]

I cannot see where that 50 comes from.

That's 5 Ohm.

 

[atferrari]

That's 5 Ohm.

12/2 ?

 

[DerStrom8]

12/2 ?

whoops, yep. Typo Should be 6 ohm.

Haha, I guess that's what I get for only skimming the posts

 

[Ian Rogers]

Ds..... Wasn't it Hans who said I need more lessons in ohms law....Ha Ha Ha....