Current Direction at 'P' Point in a Transformer

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SUMMARY

The direction of current at point 'P' in a transformer is contingent upon whether the voltage is AC or DC. With DC voltage, there is no current at point 'P' due to the lack of changing magnetic flux. In contrast, with AC voltage, the current flows to the right, influenced by the magnetic field generated by the primary coil. The discussion emphasizes the application of Lenz's Law and Faraday's Law to determine current direction and behavior in transformers.

PREREQUISITES
  • Understanding of Lenz's Law
  • Familiarity with Faraday's Law of Electromagnetic Induction
  • Knowledge of transformer operation principles
  • Basic concepts of AC and DC voltage
NEXT STEPS
  • Study the application of Lenz's Law in electromagnetic systems
  • Explore Faraday's Law in detail, particularly in relation to transformers
  • Investigate the differences in current behavior between AC and DC in transformers
  • Examine the effects of magnetic flux saturation in transformer coils
USEFUL FOR

Electrical engineers, physics students, and professionals involved in transformer design and analysis will benefit from this discussion.

Faraz Murtaza
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what will be the direction of current at 'P' point in the transformer?
 

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Since you have the symbol for DC voltage on your schematic, the answer is that there isn't a current there.

If you meant AC, to the right. Basically the second solenoid is an upside down version of the first, with magnetic field pointing down.
 
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But what will be the direction of current at point p
 
mishima said:
Since you have the symbol for DC voltage on your schematic, the answer is that there isn't a current there.

If you meant AC, to the right. Basically the second solenoid is an upside down version of the first, with magnetic field pointing down.

Can you tell the direction of current at point p?
 
Look up "Lenz law";

"An induced electromotive force (emf) always gives rise to a current whose magnetic field opposes the original change in magnetic flux."
 
So as per this definition the direction will be outside? Am I right?
 
outside what ?

did you understand mishima's comments in post 2 ?

that is did you really mean to show AC and not DC as you did ?

Dave
 
davenn said:
outside what ?

did you understand mishima's comments in post 2 ?

that is did you really mean to show AC and not DC as you did ?

Dave

On primary side the current in the coil is flowing in anti clock-wise direction, therefore the flux(mean flux path) will be upward in the first limb, but this same flux will be passing in the secondary side in the downward direction so how will we find the direction of current in it.
 
with the DC as you have shown, there will only be a very brief moment that current will flow in the secondary coil
and it will be in the opposite direction to the current flowing in the primary.
As soon as the current and hence the magnetic field in the primary reaches maximum ( and no longer varies)
current will stop flowing in the secondary.

Do you understand why?

Dave
 
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Ok fine but will happen if we take direct current?
 
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davenn said:
with the DC as yuo have shown, there will only be a very brief moment that current will flow in the secondary coil
and it will be in the opposite direction to the current flowing in the primary.
As soon as the current and hence the magnetic field in the primary reaches maximum ( and no longer varies)
current will stop flowing in the secondary.

Do you understand why?

Dave
View attachment New Doc 1.pdfyes, because in starting the voltage increases but when it reaches its maximum value then the changing flux saturates and therefore there is no rate of change of flux and hence current will stop flowing in the secondary.
fl.jpg

but my doubt is where we are using the Faraday's law in this case if i take the ac supply and the current and flux is as i shown in the attachment(let me know if it is wrong and why).
please elaborate and implement the Faraday's law in this figure.
 

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