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Resistance & Diameter of heating element

  1. Mar 29, 2010 #1


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    Design of heating element:

    Supply Voltage: 220V/3Ph/60HZ, Power: 9KW

    Resistance= VXV/P= 220X220/9000= 5.4 Ohms, But when physically when measure the resistance of wire using multimeter it is showing 17 ohms. Can you explain why there is differnece in practical and theortical value.

    Also, to find the diameter divide the found resistance by length and select the dia close to having resisitivity(R/L= Ohm/Meter) of above formula. But same as with this caluculation there is large deviation in values.

    or can anyone provide a link to the literature find the resistance & dia of heater element.

    Thanks in advance for help
  2. jcsd
  3. Mar 29, 2010 #2
    How is the heating element connected to three phase power?

    And more, we usually have 208V three phase in the US, don't we? Where does the 220V come from?
  4. Mar 29, 2010 #3


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    The elements are connected in star or Y connection.

    here KSA 220V/3PH is available.
  5. Mar 29, 2010 #4
    I see. Apparenly the voltage of each leg of the Y is 220 VAC. So from each leg to another leg is 380 VAC.

    If your heating element is connected in delta configuration, each leg of the delta should have three times the resistance of a Y element.

    380*380/9000 = 16 Ohms.
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