Step up transformers - confusion

In summary, step up transformers decrease power loss in electrical cables by increasing voltage, which decreases current and subsequently reduces the dissipation of power. While it may seem like increasing voltage could lead to an increase in power dissipation, this is not the case as the voltage drop in the cable is dependent on the current passing through it. Therefore, the second equation must be understood in the context of the load voltage.
  • #1
yllihp
11
0
I know step up transformers decrease power loss by the electrical cables, but I'm not quite sure how this works...

From what I understand, step up transformers increase voltage, hence decrease current, which means less power is dissipated by the cables since P=(I^2)R.

But then couldn't you argue that since step up transformers increase voltage, then actually the power dissipated by the cables increases since P=(V^2)/R ??

Could someone please enlighten me??
 
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  • #2
It is not like that.
Power loss in a cable is given by
Ploss =I^2 R
The voltage drop V in the cable depends on current I passing through the cable.
This V is not the applied voltage Vs. Instead
Vs= V+Vl
where Vl is the load voltage (because resistance of cable is in series with load)

So your second equation, though it is correct, has to be understood properly. A numerical example may help you to understand.
 

Related to Step up transformers - confusion

What is a step up transformer?

A step up transformer is an electrical device that is used to increase the voltage of an alternating current (AC) electrical circuit. It consists of two or more coils of insulated wire wound around a core of laminated iron, and is used to transfer electrical energy from one circuit to another through electromagnetic induction.

How does a step up transformer work?

A step up transformer works by using Faraday's law of electromagnetic induction. When an alternating current flows through the primary coil of the transformer, it creates a changing magnetic field which induces a current in the secondary coil. The number of turns in the secondary coil is greater than the number of turns in the primary coil, resulting in an increase in voltage.

What is the purpose of a step up transformer?

The purpose of a step up transformer is to increase the voltage of an AC electrical circuit. This is necessary for long distance power transmission, as higher voltages result in lower current and therefore less energy loss during transmission. Step up transformers are also used in electronic devices to convert low voltage AC to higher voltage AC for power supply purposes.

What is the difference between a step up transformer and a step down transformer?

A step up transformer increases the voltage of an AC circuit, while a step down transformer decreases the voltage. This is achieved by having a different number of turns in the primary and secondary coils. Step up transformers are used for long distance power transmission, while step down transformers are used for household power supply and electronic devices.

What are some common misconceptions about step up transformers?

One common misconception is that step up transformers can create energy. In reality, they only transfer energy from one circuit to another. Another misconception is that they can only be used for increasing voltage. Step up transformers can also be used for isolation and impedance matching in electronic circuits. Additionally, many people confuse step up transformers with voltage regulators, which are different devices used to maintain a constant voltage output.

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