Which winding in a transforemer has more number of turns?

Question

Examoogle · Accepted Answer

High voltage winding

Explanation: In an ideal transformer, the induced EMF per turn is constant for both windings. Therefore, to achieve a higher voltage level ($V_2 > V_1$), the number of turns ($N$) in that winding must be proportionally higher, as governed by the transformer EMF equation.

Working Principle: The principle of transformer action is based on Faraday's Law of Electromagnetic Induction. The induced EMF in a coil is given by $E = 4.44 f N \Phi_m$. Since the frequency ($f$) and the maximum flux ($Phi_m$) are common to both windings in the core, the ratio of voltage to turns remains constant ($V/N = constant$), necessitating more turns for higher voltage levels.

Key Formulas: $\frac{V_1}{V_2} = \frac{N_1}{N_2} = a$ — Transformer Turns Ratio Equation; $E = 4.44 f N \Phi_m$ — EMF Equation of a Transformer

Key Points: The winding with the higher number of turns is always the High Voltage (HV) winding.; The winding with the lower number of turns is always the Low Voltage (LV) winding.; This relationship holds true regardless of whether the transformer is Step-up or Step-down.; Turns ratio defines the magnitude transformation of voltage and current.

Advantages: Allows efficient power transmission by stepping up voltage.; Enables safe usage of electrical equipment by stepping down voltage.

Disadvantages: Core losses (hysteresis and eddy current) increase with higher winding resistance/turns.; Increased copper losses due to larger wire lengths in HV windings.

Applications: Power grid transmission and distribution.; Power supplies for electronic devices.; Impedance matching in communication circuits.

Additional Info: In a step-up transformer, the Secondary is the HV winding (more turns).. In a step-down transformer, the Primary is the HV winding (more turns).. Options C and D are incorrect because the primary or secondary designation depends entirely on the direction of power flow, not the number of turns.

Answer: B is correct — The winding designed to operate at a higher voltage level necessarily requires a greater number of turns to satisfy the constant flux linkage condition.

Exam Tip: Always remember the mnemonic: 'More Voltage = More Turns', regardless of primary or secondary labels.

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