Final answer:
Larger capacity transformers above 600 volts are wound for step-down polarity, where the primary voltage is higher than the secondary voltage, reducing voltage levels for safe and efficient distribution to consumers.
Step-by-step explanation:
Larger capacity and high-voltage transformers (greater than 600 volts) are typically wound for step-down polarity. This means that the primary voltage is higher than the secondary voltage, which is a characteristic of a step-down transformer. A transformer changes voltages at several points in a power distribution system to limit energy losses and ensure safety.
For instance, electric power is often generated at greater than 10 kV and transmitted at voltages over 200 kV, and even up to 700 kV, which is then stepped down to levels between 120 V to 480 V for consumer use. The principle governing the operation of transformers is that the ratio of the secondary to primary voltages equals the ratio of the number of turns in their windings. For a step-down transformer, the ratio is less than one since it decreases voltage and increases current.