Message Board Thread - "Transformer heated screws"

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Transformer heated screws nickinfrared 9/30/2005
During an ispection at a large transformer I found these heated screws.
What do you advise me:
1.to tight;
2.to replace;
3.to ignore it;
4.to begin a case study?
Thank you.
 
Re:Transformer heated screws Bob Berry 9/30/2005
These screws are more than likely heated by induction, there are many factors that contribute to this. The easiest way to prevent it is to replace the screws with non-ferrous stainless steel screws. You will of course have to use ones having the same tensile strength, lenght and size.
 
Re:Transformer heated screws IRJay 9/30/2005
The screws are being affected by the surrounding magnetic fields. This induced current then presenting itself as heat. These screws have become isolated from the surrounding grounded metals by paint or corrosion. Either replace with non ferrous metal type screws such as stainless steel or re-establish the correct bonding by cleaning the surfaces at the bolts.
 
Re:Transformer heated screws Pony 10/4/2005
Ref: "Heated Screws"

This I have found on a number of Transformers located outside and in poor condition. Corrosion and bad grounding has been confirmed as being the cause. Not common to find this on transformers inside however the cable clamps are usualy made of hard wood or other insulating material and I have found clamping "Bolts" at temperatures as high as 80 C. Indution (Eddy) currents are the cause however this is more noticable around cable gland plates which should be well grounded. A pocket "Gauss" meter indicates a stronger field by such defects.


 


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