Question

How can energy losses in a transformer be minimised?

Hint:

In a transformer, reducing the resistance of the wires minimizes energy losses, as power loss is proportional to the square of the current and the resistance.

Answer 1

Step 1: Understanding the energy loss in a transformer.
The energy losses in a transformer are mainly due to resistance in the wires. The power loss due to resistance is given by the formula: \[ P_{\text{loss}} = I^2 R \] where \( I \) is the current and \( R \) is the resistance.
Step 2: Minimising energy losses.
To minimise energy losses, we need to reduce the resistance \( R \). This can be achieved by using thicker wires, as thicker wires have lower resistance. Thus, by decreasing \( R \), the power loss \( P_{\text{loss}} \) also decreases.
Step 3: Conclusion.
Therefore, energy losses can be minimised by using thick wires to reduce the resistance.

Answer 2

Step 1: Most energy loss in a transformer happens because its wires have resistance, and power lost = I² × R.

Step 2: To cut this loss, we need to lower the resistance R of the wires.

Step 3: Using thicker wires lowers their resistance.

Step 4: So transformer losses are minimised mainly by using thicker, lower-resistance windings.

Answer 3

Resistive (copper) loss is only part of the picture. A changing magnetic flux also induces swirling eddy currents inside the iron core itself, wasting energy as heat, and the core material also loses energy each cycle to hysteresis as its magnetisation reverses.
The eddy-current loss is cut down by building the core from thin, electrically insulated laminated sheets instead of one solid block, which breaks up the paths available to those swirling currents. Hysteresis loss is reduced by choosing a magnetically "soft" core material with a narrow hysteresis loop, such as silicon steel.
So beyond just thickening the windings, laminating the core and picking a low-hysteresis core material are the key extra ways transformer losses are minimised.