Red Seal Industrial Electrician Practice Exam

What defines reactive power in electrical systems?

1. Power that performs useful work

2. Power that flows in only one direction

3. Power oscillating between source and load

4. Power that is lost as heat

The correct answer is: Power oscillating between source and load

Reactive power is defined as power that oscillates between the source and the load in an alternating current (AC) electrical system. This occurs due to the presence of inductive and capacitive elements in the circuit, such as motors and transformers, which store energy temporarily and then release it. In reactive power, the energy does not perform any net work, but it is essential for maintaining the voltage levels necessary for active power (the power that performs useful work) to be delivered effectively. This back-and-forth flow of energy helps stabilize the system; thus, without reactive power, voltage levels could fluctuate wildly, causing inefficiencies and instability in the system. Understanding reactive power is important for industrial electricians, as it affects the overall performance and efficiency of electrical systems. By managing reactive power, one can enhance the quality of power and reduce losses associated with voltage drops.