Final answer:
To prevent injury, the secondary winding of a current transformer must be short-circuited. In a step-down transformer, the primary voltage is higher than the secondary and the primary current is lower than the secondary.
Step-by-step explanation:
To prevent injury while working on a current transformer, the secondary winding must be short-circuited. When the secondary winding of a current transformer is open-circuited, the current in the primary can induce very high voltages in the secondary due to the lack of a current path, potentially leading to dangerous conditions. Short-circuiting the secondary winding ensures that the induced secondary current has a low-resistance path to flow through, thereby maintaining the voltage at a safe level.
As for the facts about step-down transformers, it is true that in a step-down transformer, the primary voltage is higher than the secondary voltage. This means that the voltage is decreased from the primary side to the secondary side. Additionally, because of the conservation of power (assuming ideal conditions), the primary current is lower than the secondary current, as the product of current and voltage (power) remains relatively consistent across the transformer, taking losses into account.