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Transformer 110v not working. Can I check if fixable before buying a new one?

Discussion in 'Electrics UK' started by Jonny Vee, 18 Feb 2020.

  1. Jonny Vee

    Jonny Vee

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    I have a 5Kv transformer 110v for my tools that suddenly stopped working. Checked the fuse on the plug and is fine. With plug off I removed the cover and inside seems to be a block of glue which I believe the transformer is inside it.


    Is there any way to check what happen or just have to through away? It`s a £200 item damn.


    Thanks
     
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  3. RF Lighting

    RF Lighting

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    There’s normally an overload button on the side near where the flex entry is. Check that this hasn’t popped out first of all
     
  4. Jonny Vee

    Jonny Vee

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    I can see it and seems to be completely inside.
     
  5. DetlefSchmitz

    DetlefSchmitz

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    You might try measuring the primary and secondary resistances.
     
  6. Jonny Vee

    Jonny Vee

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    I got a multi meter but no idea how to do that. Any suggestion on what to do?
     
  7. Nozzle

    Nozzle

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    You can claim back some of your £200 purchase if it really is broken...

    There's a lot of copper in those, and last time I traded in some old copper pipe the scrappies will give £3500/tonne... how many kilos you got there buh!! Break it out of the housing and plastic and clean it up as best you can. (That was the rate for uncontaminated copper)

    Nozzle
     
  8. Jonny Vee

    Jonny Vee

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    Is there anyway to check if the overload button is faulty and need to be replaced?
     
  9. Jonny Vee

    Jonny Vee

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    it`s easy 15-17kg but still not worth that money. Hopefully can fix it and no idea who would take the old copper on my area
     
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  11. ericmark

    ericmark

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    At 5 kVA not a yellow brick, so there should be some output over loads, with small 1.8 kVA the output at 16A is about 10 amp input so often only a input over load, even at 3 kVA seen it with only input, wrong as 3 kVA = 50 odd amp one output phase to earth, but still done.

    But at 5 kVA that is well over the top so would need output brakers some where. Looking at close to 100A to earth before it would trip an input over load.

    Potted windings are unusual on 5 kVA, with yellow bricks very common, but at 5 kVA normally a tin box.
     
  12. DetlefSchmitz

    DetlefSchmitz

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    Set meter to Ohms. Measure primary between the L and N pins in the plug. Measure the secondary between the L and N of the built in socket. Dunno how much it should be but definitely single digit Ohms.
     
  13. SFK

    SFK

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    Detlef, beat me to it.
    Do as he says first.

    If high ohms (or more likely open circuit / infinite ohms) I would then open it up and test the overload button with meter set to ohms to see if that switch is open or closed circuit (you want to see v low resistance).

    I would then test the (external) lead wire going to unit itself in case it has in internal break. One test lead on live on plug and other test lead on internal brown wire testing for resistance. Repeat for N and earth. (you want to see v low resistance).

    If sold lump of glue is to the top if case then you will have problem/impossible fixing these suggestions as they will be encapsulated.

    Nice video here, go to 16min for resistance test:
     
    Last edited: 18 Feb 2020
  14. Jonny Vee

    Jonny Vee

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    Replaced with another fuse and seems working but I just believe it ****ed up my hammer drill. I plugged in and hammer just moved for a second. I thought was something wrong and measured the voltage with a reading of 145.2v. Do I have to bin before I kill all my tools?
     
  15. ericmark

    ericmark

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    The whole idea of the 110 volt is it isolates the 230 volt supply, to get 145.2 volt it clearly is not isolating the supply, I wonder if it's a proper site transformer?

    You can drop the voltage using an auto transformer, not permitted for UK site use, some thing is wrong, how about some pictures, it does not make sense.
     
  16. Jonny Vee

    Jonny Vee

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    It's definitely a UK site permitted 110v transformer. It's been used on site for a while.
     

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  17. mattylad

    mattylad

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    how about a photo of the inside?
     
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