NEIEP Elevator Installation and Maintenance 400 Practice Exam

In a transformer, an increase in the load on the secondary side leads to a corresponding increase in the primary current. This is because transformers operate on the principle of conservation of energy, which states that the power input to the transformer (in the primary winding) must equal the power output (in the secondary winding), minus any losses.

When the load on the secondary side increases, it requires more power to be supplied. Since power (P) is related to current (I) and voltage (V) by the formula P = IV, an increase in the load will result in an increase in the secondary current. To maintain the balance of power, the transformer must draw more current from the primary side to support the increased demand on the secondary as it provides more output power. This causes the primary current to increase.

In summary, as the load on the secondary side increases, the primary current must increase to ensure that the transformer can deliver the required output power.