- #1
Current Direction at 'P' Point in a Transformer
- Thread starter Faraz Murtaza
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- Current Direction Point Transformer
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Discussion Overview
The discussion revolves around determining the direction of current at point 'P' in a transformer, considering both DC and AC scenarios. Participants explore the implications of different voltage types on current flow and the underlying principles of electromagnetic induction.
Discussion Character
- Debate/contested
- Technical explanation
- Conceptual clarification
Main Points Raised
- Some participants assert that if the schematic shows DC voltage, there would be no current at point 'P'. Others suggest that if AC is implied, the current would flow to the right.
- One participant references Lenz's law, indicating that an induced electromotive force (emf) creates a current whose magnetic field opposes the change in magnetic flux.
- Another participant questions the meaning of "outside" in relation to the direction of current and seeks clarification on whether AC or DC was intended in the original schematic.
- It is noted that with DC, current in the secondary coil would only flow briefly and in the opposite direction to that in the primary coil, ceasing when the magnetic field in the primary stabilizes.
- A participant expresses confusion about the application of Faraday's law in the context of AC supply and requests elaboration on how it relates to their provided figure.
Areas of Agreement / Disagreement
Participants do not reach a consensus on the direction of current at point 'P', with multiple competing views regarding the effects of DC versus AC and the application of electromagnetic principles.
Contextual Notes
There are unresolved assumptions regarding the type of voltage represented in the schematic and the implications for current flow. The discussion also highlights the need for clarity on the application of Faraday's law in the context presented.
- #2
mishima
- 576
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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.
If you meant AC, to the right. Basically the second solenoid is an upside down version of the first, with magnetic field pointing down.
- #3
Faraz Murtaza
- 32
- 0
But what will be the direction of current at point p
- #4
Faraz Murtaza
- 32
- 0
mishima said:
Can you tell the direction of current at point p?
- #5
SirAskalot
- 141
- 0
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."
"An induced electromotive force (emf) always gives rise to a current whose magnetic field opposes the original change in magnetic flux."
- #6
Faraz Murtaza
- 32
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So as per this definition the direction will be outside? Am I right?
- #7
davenn
Science Advisor
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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
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
- #8
Faraz Murtaza
- 32
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davenn said:
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.
- #9
davenn
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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
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
Last edited:
- #10
Faraz Murtaza
- 32
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Ok fine but will happen if we take direct current?
- #11
Faraz Murtaza
- 32
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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.davenn said:
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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