GREAT video!!! I am using 18 gauge nichrome wire as a dummy power resistive load. Do you know how a maximum current or wattage load can be calculated for a given nichrome wire, as not to damage it? For example a 1 meter length of 18 gauge wire in air at room temperature? Similar to the way nichrome wound power resistors have power ratings. THANKS MUCH!!!
The maximum operating wattage/current depends on the application as governed by the NEC code. You can download my spreadsheet from my website and do the calculations.
Sir this was confusing me a lot, so there is no simlpe formula, to find wire temprature, unless we get them expermentally, but now we can aproximate all by saying for example,the energy in,I*V, Which is dependent on the resistance of the wire, determines the temprature of the wire, assuming all other things are keept the same for identical wires( nichrome 80 or 60) of different length and diameter( eg 0.9mm and 0.7mm) Thanks you for the best explanation and insights
Metal is a sponge that soaks up heat. Therefore the calcs must be done over time to get how much heat is soaked up between each time interval. Wire temp is not a single calculation like converting degrees F to C. The graph I show is required because air "boils" on the surface of very hot wire. As the wire heats, more air boils faster.
Greate video! i have a question. Does your equation assume that the current and resistance is constant. I thought that it would be necessary to recalculate these values between timesteps since the wires temperature rises. But as i am writing this, i see that the current and resistance are just used for power (I*R) so I guess it isn't necessary hehe
For 99.9% of the daily applications assuming a value for energy in is more than adequate. You can iterate the change of Energy-In as resistance changes with temperature. The approach in this video (ignoring change in resistance with respect to rising wire temperature) is adequate even when performing heat transfer on ultra fine wire gages (58 or finer) in vacuum tubes (which I haven't published yet). Thanks for watching and commenting.
I'm doing something wrong. My calc is for Kanthal A-1 and the E-net goes to negative because my E-rad grows larger than the input. Do you have a spreadsheet I can plug my Kanthal A-1 values into?
The air around around the wire is a "layer". If stagnant it will have a temperature profile (hot near the wire and cooler the further away it is). The brick of the kiln is a layer, the insulation between the brick and the kiln case (steel?) is a layer, the case is a layer and you can stop the calculation. Or, treat the case as a layer, the air outside the case as a layer, the building the kiln resides in is a layer. The thermal radiation, emissivity, etc. of the buildings' outside has radiation, emissivity, conduction, calculations. The point is this: the heat transfer is the same set of calculations for radiation, conduction and emissivity. Each layer has values for thermal (k) component, specific heat, etc. Each layer has the same calculation and the spreadsheet simply gets wider and wider and wider.
You, sir, are truly amazing. Very thorough and complete explanation. Thank you!
Hi, is there a link to download the software or the CSV file, this is amazing work and would come in very handy.
Sir, are truly amazing. Very thorough and complete explanation and very very useful.
Brilliant start for my understanding of nichrome wire. Thank you
GREAT video!!!
I am using 18 gauge nichrome wire as a dummy power resistive load. Do you know how a maximum current or wattage load can be calculated for a given nichrome wire, as not to damage it? For example a 1 meter length of 18 gauge wire in air at room temperature?
Similar to the way nichrome wound power resistors have power ratings.
THANKS MUCH!!!
The maximum operating wattage/current depends on the application as governed by the NEC code. You can download my spreadsheet from my website and do the calculations.
Sir this was confusing me a lot, so there is no simlpe formula, to find wire temprature, unless we get them expermentally, but now we can aproximate all by saying for example,the energy in,I*V, Which is dependent on the resistance of the wire, determines the temprature of the wire, assuming all other things are keept the same for identical wires( nichrome 80 or 60) of different length and diameter( eg 0.9mm and 0.7mm) Thanks you for the best explanation and insights
Metal is a sponge that soaks up heat. Therefore the calcs must be done over time to get how much heat is soaked up between each time interval. Wire temp is not a single calculation like converting degrees F to C. The graph I show is required because air "boils" on the surface of very hot wire. As the wire heats, more air boils faster.
Really amazing video thank you so much
Very informative video. What parameters should I change when I have an insulated copper wire?
Greate video! i have a question. Does your equation assume that the current and resistance is constant. I thought that it would be necessary to recalculate these values between timesteps since the wires temperature rises. But as i am writing this, i see that the current and resistance are just used for power (I*R) so I guess it isn't necessary hehe
For 99.9% of the daily applications assuming a value for energy in is more than adequate. You can iterate the change of Energy-In as resistance changes with temperature. The approach in this video (ignoring change in resistance with respect to rising wire temperature) is adequate even when performing heat transfer on ultra fine wire gages (58 or finer) in vacuum tubes (which I haven't published yet). Thanks for watching and commenting.
Thanks this video clearly explained my questions!
coolest tool ever
Your formula for Stefan boltzmann constant should be 5.67036713 E-08 not 5.67036713 e-08 to avoid confusion with Euler's number
Agreed, and in future videos I will use "E" or X10^-8 to be clearer. Thanks!
Where i can download the program please
Great video tutorial ❤ thank you for sharing your knowledge and experience 🇵🇭🫡
You are an amazing hero. Please can you upload the pdf, thank you
I'm doing something wrong. My calc is for Kanthal A-1 and the E-net goes to negative because my E-rad grows larger than the input.
Do you have a spreadsheet I can plug my Kanthal A-1 values into?
I uploaded an example spreadsheet to my website under the Programs tab.
Can you put a link in the description for the chart you were working from? Thx and YESHUA GOD ALMIGHTY bless you!
Good
What about if your wire is in a kiln and the air temp is changing with time?
The air around around the wire is a "layer". If stagnant it will have a temperature profile (hot near the wire and cooler the further away it is). The brick of the kiln is a layer, the insulation between the brick and the kiln case (steel?) is a layer, the case is a layer and you can stop the calculation. Or, treat the case as a layer, the air outside the case as a layer, the building the kiln resides in is a layer. The thermal radiation, emissivity, etc. of the buildings' outside has radiation, emissivity, conduction, calculations.
The point is this: the heat transfer is the same set of calculations for radiation, conduction and emissivity. Each layer has values for thermal (k) component, specific heat, etc. Each layer has the same calculation and the spreadsheet simply gets wider and wider and wider.
@@deepblueharp thanks!
Thank you!