Electrical Machines: Voltage Calculation Quiz

Ideal Transformer Characteristics

• In an ideal transformer, the primary and secondary are related by the turns ratio, which determines the voltage and current transformations.

Ideal Transformer Under Load

• When a load is connected across the secondary, the secondary voltage does not change because the ideal transformer maintains a constant turns ratio.
• The formula for calculating the secondary current (I2) in an ideal transformer under load is I2 = I1 * (N1 / N2), where I1 is the primary current, N1 is the primary turns, and N2 is the secondary turns.
• The primary must develop a magnetomotive force (MMF) to counterbalance the secondary MMF (N2I2) in an ideal transformer under load.

Ideal Transformer Circuits

• The primary to secondary turns ratio of the ideal transformer in a circuit is N1 : N2, where N1 is the primary turns and N2 is the secondary turns.

Solving Circuit Problems

• It is suggested to shift all impedances to the primary side of the transformer when solving circuit problems involving transformers to simplify the analysis.

Impedance Matching Transformers

• Impedance matching transformers are primarily used to match the impedance of a source to a load in AC work to maximize power transfer.
• A key characteristic of impedance matching transformers compared to power transformers is that they have a 1 : 1 turns ratio, which allows for maximum power transfer.

Instantaneous Current and Flux

• For the required instant-to-instant bucking effect in an ideal transformer under load, the instantaneous current in the primary must be equal and opposite to the instantaneous current in the secondary.
• The instantaneous current in the primary and secondary are related by the turns ratio (N1 : N2).
• The flux and Eg (induced voltage) in an ideal transformer under load are in phase.
• It is essential for an ideal transformer under load to have currents I1 and I2 in phase to maintain the ideal transformer operation.