Here's why:
* Turns ratio is a fundamental property of the transformer: It represents the ratio of the number of turns in the primary winding to the number of turns in the secondary winding.
* Voltage and current are related to the turns ratio: The voltage ratio is directly proportional to the turns ratio, while the current ratio is inversely proportional.
* Phase voltages and currents are important for specific applications: They are relevant when analyzing three-phase transformers or when dealing with the phase relationships between the primary and secondary.
Formula for turns ratio:
* Np/Ns = Vp/Vs = Is/Ip
Where:
* Np = number of turns in the primary winding
* Ns = number of turns in the secondary winding
* Vp = voltage on the primary winding
* Vs = voltage on the secondary winding
* Ip = current on the primary winding
* Is = current on the secondary winding
To summarize:
* The turns ratio is calculated using the primary and secondary voltages and currents.
* Phase voltages and currents are not directly used in the turns ratio formula but are important for specific analyses.
