1
\$\begingroup\$

I'm a bit confused since people said those resistors would draw more power the lower its resistance is, and one way to reduce its resistance is reduce its length.

  • Will it draw more power the shorter it is?
  • If so, will it stop working past certain point due to temperature being too high?
  • If yes, how to find the safe operating range for that heating resistor?

Currently I'm making a heater with "Nikelin" wire as a resistor heater in the form of a coil. I can't find the specification sheet for it anywhere. That "Nikelin" might be called something else in other places. All I know is that it is called that here in Indonesia. I can't even find the manufacturer. Only see it being sold in online and electronic stores.

\$\endgroup\$
1
  • \$\begingroup\$ I can't read Bahasa Indonesia but this page might be saying that nikelin is the same as nichrome, which is the name for a common heater wire in the English-speaking world. \$\endgroup\$
    – The Photon
    May 10, 2022 at 15:15

3 Answers 3

2
\$\begingroup\$

Your heater specifications are as shown below.

enter image description here

20 AWG (2mm diameter) Nichrome wire can carry much more than 26.24 A.

15 m of wire would be required per phase to wind an air-heating element.

\$\endgroup\$
8
  • 1
    \$\begingroup\$ Where do you get the 2000 °C and 1000 °C from? \$\endgroup\$
    – Hearth
    May 11, 2022 at 13:44
  • \$\begingroup\$ @Hearth - Hi! Thank you for your feed back. Had mentioned °C instead of °F. The error has been rectified. \$\endgroup\$
    – vu2nan
    May 11, 2022 at 14:00
  • \$\begingroup\$ It doesn't matter whether it's °C or °F--where do you get the numbers from? I'm not sure how you can compute operating temperature without information on environmental conditions. \$\endgroup\$
    – Hearth
    May 11, 2022 at 14:01
  • \$\begingroup\$ The numbers are from here. easycalculation.com/engineering/electrical/… \$\endgroup\$
    – vu2nan
    May 11, 2022 at 14:04
  • 1
    \$\begingroup\$ @Hearth - I have edited out those numbers. \$\endgroup\$
    – vu2nan
    May 11, 2022 at 15:00
3
\$\begingroup\$

will it draw more power the shorter it is?

Yes, assuming your power supply is able to provide enough current.

if so, will it stop working past certain point due to temperature being too high?

The resistor can only get so hot before it burns or melts.

if yes, how to find the safe operating range for that heating resistor?

If nikelin is the same as nichrome wire, you need to keep the temperature below 1400 C (at every point on the wire) to avoid it melting. You could either do that experimentally (heat up some wires and see if they melt), or possibly by monitoring the resistance of the wire (which will depend on temperature).

If you want to reduce the resistance while increasing the power capability, put more resistors in parallel rather than shortening the one you have.

\$\endgroup\$
9
  • \$\begingroup\$ Of course, you also need to make sure the supports holding the wire are able to handle the temperature as well! Kind of obvious, but possibly easy to overlook. \$\endgroup\$
    – Hearth
    May 10, 2022 at 15:40
  • \$\begingroup\$ @Hearth, you could just make the supports out of a fatter chunk of nichrome. \$\endgroup\$
    – The Photon
    May 10, 2022 at 15:41
  • \$\begingroup\$ How do i control that wire assuming i could draw a lot of power from industrial power supply? limiting the current? adding more resistance? using certain tool? (im new to this, i dont even know if such method is possible or such tool exist) \$\endgroup\$
    – Bramble
    May 10, 2022 at 15:41
  • \$\begingroup\$ @Bramble how much power do you need? Milliwatts? Watts? Kilowatts? \$\endgroup\$
    – The Photon
    May 10, 2022 at 15:42
  • \$\begingroup\$ its around 10 kilowatts range, i dont know the specified power available, but people i asked says its 3x125A 220V \$\endgroup\$
    – Bramble
    May 10, 2022 at 15:43
3
\$\begingroup\$
  1. Don't buy anything without a datasheet unless you know exactly what to expect.

You link only translates to

Material composition resistance wire, base: iron-chromium-aluminum (FeCrAl). low resistance, magnetic.

You need 1.76 ohms (hot) per phase which can be a matrix of series and parallel resistance. The temperature rise affects reliability and also raises resistance so choose your requirements from this. Magnetic wire will also exert a force on other magnetic materials.

Wire that does not corrode can last a long time but at high temperatures the failure rate is accelerated by 2x for every 10'C rise, so choose a temperature that barely emits visible IR light for long life.

This requires more material unless this uses forced-air or liquid heat-spreading.

Beware of metal migration into a fluid and outgassing creating hot-spots.
This must be homogeneous. Stirring the medium is essential, if not critical at high heat density.

You are using 220V high voltage and expect 220V/125A = 1.76 ohms for the hot resistance on a 3 phase grid. The two variables that affect the temperature rise are the power density or W/mm^2 of surface of the wire to the surroundings and thus the resistance / m with I^2R=Power.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.