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Updating heating elements in an older powder coating oven

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  • Updating heating elements in an older powder coating oven

    Our powder coating oven is old, but it is sound structurally and the controls still work but the elements are not heating completely. The oven is 3 phase 208V and pulls 50 amps when running. We have confirmed each lead of the cable providing power to each element wire is getting the correct power at the element connection. The elements are the old style with a single bare wire (about 1/16" in diameter) running thru ceramic components. I would like to upgrade the elements; I am willing to upgrade the controller as well if I need to.
    All advice is apricated

  • #2
    Why do you think the current elements aren't working? If you're convinced they're not, you need to provide a little more information. Are the elements truly 3pH or are the elements just using 2 of the 3 phases available each? Simply put, are there 2 or 3 connections to each element? True 3pH elements typically split the phases and power multiple internal element loops that use 2 phases each. If that the case then it's very possible that one of the internal element loops has burnt out, thus reducing the elements's available wattage. Simplest fix in this case would be to acquire similar 3pH elements to replace existing.

    3pH is mostly reserved for electric motors as they can truly benefit from the 3 independent phases. Heating elements regardless of type only require 2 phases to function, therefore 3pH elements will always have multiple internal electrical loops, using either 3 loops to form a balanced load or 2 loops, unbalanced.
    Metal Finishing Guru
    Last edited by ed_denu; 01-08-2022, 11:53 AM.


    • #3
      Thank you for the reply, we are having trouble getting the oven up to temp in a reasonable amount to time. When we looked at the elements, we could see they were not heating completely. I have attached three photos for your review. The first one is of the inside of the control cabinet that is providing power to the elements. The two red arrows are pointing to the power supply of the elements. The second photo is of the heating elements connection. I realize there is a lot of corrosion on the connections. We intend to clean them to see if that will help but I am very concerned if something breaks or twist into when we take it apart, I will not be able to replace the parts. That is why I decided to check on replacing the elements.

      Click image for larger version

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      Again, thank you for the help
      Best Regards


      • #4
        Here is the third photo for the previous comment. This is the only tag that is on the oven, I do not know how to contact the manufacture for parts.
        Click image for larger version

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        • #5
          My Chinese isn't very good so the third picture doesn't help much. The photo of the electronic controls is rather blurry so also not much help. IMO you have two choices. First would be to acquire some 3pH elements, swap them in and see how that works. You might need to change the wiring slightly to accommodate the new 3pH elements based on connection points which will be determined by the number of internal element loops. This would assume all other components are in working order and would probably be your best option if you are ok with working with electrical wiring, etc. The other option would be a complete swap for newer components, pid, relay timers, etc.

          Keep in mind that 3pH elements do not actually heat using all 3 phases to a single resistance loop. If you search you'll see various 3 phase elements and how they split the phases to power the element.

          Only other thing you might attempt first would be to do a resistance test on the elements to determine if they are burnt(open). If not "open" you can determine wattage by using ohms law calculations. Wattage = voltage2 / resistance. Good luck.
          Metal Finishing Guru
          Last edited by ed_denu; 01-09-2022, 09:23 AM.