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Transformers question (1 Viewer)

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Energy losses occur thru eddy currents due to heat thru resistance. Therefore by cooling the laminated iron core there will be less eddy currents and therefore less energy losses. (increased heat bring increased resistance due to atoms vibrating more)
 

Shael

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Well its a step up transformer for that reason. Stepping up the voltage, means the current must come down. From the powerloss equation:

P = I^2 R

Thus if we lower 'I', the powerloss is reduced.
 

serge

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Shael said:
Well its a step up transformer for that reason. Stepping up the voltage, means the current must come down. From the powerloss equation:

P = I^2 R

Thus if we lower 'I', the powerloss is reduced.
but that's not a technique of reducing heat loss...
if you want 20 volts, you'll make a transformer for that
purpose
 

helper

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No shael, digital is correct.
In an ideal transformer, up or down, Energy is conserved.
P=IV.
Increases I, decreases V.

You are talking about power transmission.
 

sikeveo

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the question was from my trial and it was 3marks. I wrote what digitalfortress said and got 0.

So helper, is that all?
 

jake2.0

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the soft iron core is there to intensify the magnetic field so i guess it does reduce power loss, as it reduces waste
 

Shael

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I'm still correct, but yes I read it wrong and what Im talking about is powerloss in transmission. Still, by upping the voltage you drop the current because of conservation of energy, so it works either way, if one goes up, the other must go down.

Less current = less heat = less powerloss, as from the damn equation.

As for inside the transformer, they use:

- laminated iron core to reduce eddy currents (as Digital said)
- circulating oil to move the heat produced away from the core
- cooling fans and fins to cool the oil being circulated
 

helper

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Sikevo, it depends on how pedantic your teacher wants to be.

Firstly no energy is lost in a transformer it is converted into other forms that are not desirable.
To maximise energy transfer you need to remove these undesirable energy changes.

Firslt you want to have a maximium intensity magnetic field produce by the primary coil. This is done by the use of a soft iron core, concentration of the coils into a minimium area.

You then want a maximum overlap between your secondary coil and your primary coil, to ensure a maximum amount cross over in the magnetic flux of the two coils.
The coating of the wires are also important here as you want maximum magnetic permabilty but minimum electric conductivity.
Your wire thickness has to be looked at, with the secondary coil in a step up being thinner as you are producing a smaller current but both coils must have an appropriate thickness to minimise heating effects.

The major undesirable energy is heat energy, through eddy currents in the core. The laminations reduce these.

Heating effects need to removed, so it is desirable to have the transformer cooled to remove heating effects that increase resistance.
 

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