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Automatic Ignition

  • Ignitor - 24V power supply + nichrome wire
    • Uxcell FeCrAl 1mm 18 Gauge AWG 0.45 Ohms/ft Heater Wire 7.5Meters
    • FeCrAl(22% Cr,58% Al,Fe Balance);
    • Brand: DMiotech
    • Average Wire Diameter: 1mm; Wire Gauge: 18 AWG
    • Wire Length: 7.5M / 25Ft; Melting Temperature: 1500C (2730F)
    • Max. Operating Temperature: 1250C (2282F); Resistance/Foot: 0.45 Ohms/ft (1.477 Ohms/m)
  • Power dissipation - Use 120V for faster activation
    • V=IR
    • I=V/R
    • For 20A, Resistance should be
      • 20A=120V/6 ohms
      • Better to use 12V
      • 20A=12V/0.6 ohms
    • -> Need 1.3 feet of nichrome

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Automatic Ignition

  • Current required for a given temperature of wire:

  • Design consideration: run as much current as possible for as short a time as possible to get quick heating and ignition within ½ second after gas is turned on
  • Logic:
    • Turn on the ignitor at 20A, 2 kW
    • Wait ½ second
    • Turn on the acetylene for immediate lighting
    • Wait ½ second
    • Turn off ignitor
  • Auto ignition temperature - 581F

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Gas System + Ignition

Cutting Oxygen

Heating Oxygen

Heating Acetylene

Heating

Shutoff

Oxygen Lance

Nichrome Ignitor - 20A

120 AC

12 VDC

12 VDC

12 VDC

12 DC

20A

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Gas System - Oxygen Hose is Split into 2

Hookup