An interesting Phenomenon

Discussion in 'The Family Room' started by BundyRoy, Nov 30, 2015.

  1. BundyRoy

    BundyRoy Senior Elf

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    Yesterday I was making up some leads. Last year I got a new light for my workbench and a new heat gun for Christmas. I had both plugged into a power board and when I use the heat gun on high the light bulb (28 watt thread type incandescent) fluctuates from normal to dull in a quick cyclic pattern. The heat gun is 2000W, so no bigger draw than a kettle I assume. My house has been rewired so I figure that is/should be fine. I figure its either an issue to do with the extension cord/power board (5m extension cord) or the heat gun. Any electricians out there have any ideas.

    And yes I know 28W is not an ideal work bench light but if you just tell your wife that you need a new light for the work area and your work area is also her art/craft area than you should expect a trendy not so useful light instead of a 500W portable utility light. I know that now.
     
  2. scamper

    scamper Senior Elf

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    I would say you are loading the power board very close to its limit.
    2000w heat gun is around 8 amps, standard power board is rated to 10 amps, but if it a cheap board, then they would have used the smallest cable possible and then you have to allow for voltage drop and inefficiencies in the switch, plugs and sockets etc.
    Added to that, I am sure you have loaded the whole circuit to breaking point at your work bench if you are like any of us with computers, test instruments, a radio, soldering iron, fridge for your bevies.
    The light is just showing you the truth, the computer will show you in a more subtle way like crashing or losing data :)
     
  3. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    I would also say that the 5 metre extension cable is a very cheap brand as well and may only be using the minimum required gauge sized cable
    The light is behaving this way due to voltage drop, the lights share the same circuit as the heat gun and both go through the extension, so when the heat gun is on the voltage supplied to the lights is lower and thus it appears dimmed, the effect you are seeing with the lights is caused by the temperature control of the heat gun as it fluctuates power to maintain the desired temperature
     
  4. David_AVD

    David_AVD Good news, everyone!

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    I have seen some weirdness when heat guns are used on the lower power setting.

    This is because a diode is added into the circuit and this causes an unbalanced current draw.

    Other (sensitive) loads can react badly to this "ripple".
     
  5. OP
    OP
    BundyRoy

    BundyRoy Senior Elf

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    Because I have temporarily taken over my wifes work area there is not much else plugged in. Only the heat gun, light and when I'm using it, the soldering iron. You are right though with the cheap power board and the extension cord. Will swap these out and see if things improve.

    Thanks for the tips.
     

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