Dc supply to transformer

In summary, the conversation discusses the accidental use of a DC supply on a transformer in a college lab, resulting in a blown fuse. It is explained that transformers typically work with AC voltage and that for DC voltage, they act like a short wire with low resistance. The speaker also suggests that the person asking for an explanation should already know the answer if they are working with transformers in a lab. It is also mentioned that the transformer's iron core acts like an electromagnet and produces a back emf which delays the increase of DC current, leading to the blown fuse.
  • #1
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my friend gave a dc supply to a transformer in my college lab accidentally and the fuse went off can i get an explanation on why this happened?
 
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  • #2
Transformer work only with AC voltage. For DC transformer act just like a short wire (a very small resistance ).
 
  • #3
Jony130 said:
Transformer work only with AC voltage. For DC transformer act just like a short wire (a very small resistance ).
Can you please explain how a transformer shows very small resistance to a DC supply?
 
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  • #4
Actually this sounds like a disguised homework question. If you are messing with transformers in lab you should already know the answer to the question.
 
  • #5
Because transformers is essentially just two or more coils of wire wrapped around the core. And wires has "low" resistance.
 
  • #6
dhivakhar said:
my friend gave a dc supply to a transformer in my college lab accidentally and the fuse went off can i get an explanation on why this happened?
You have a careful smart friend
 
  • #7
Actually, if your friend had been able to measure the way the current varied around the time of switch on, he would have found that the current value followed a curve, because the Iron core of the transformer behaves like an electromagnet. The magnetic field energy takes time to build up and it produces a 'back emf' which delays the DC current increase (This would be fairly quick with a mains transformer - only a few tens of milliseconds before the fuse started to blow.)
 

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