Tehonottotekijät

Tehonottotekijät, often translated as "power factor" in English, refers to the ratio of real power to apparent power in an electrical system. Real power, measured in watts (W), is the power that performs useful work, such as heating or running a motor. Apparent power, measured in volt-amperes (VA), is the total power supplied to a circuit, including both real power and reactive power. Reactive power, measured in volt-amperes reactive (VAR), is the power that oscillates back and forth between the source and the load, and does not perform useful work.

A high tehonottotekijä, meaning close to 1, indicates that most of the power supplied is being used for useful work. A low tehonottotekijä suggests that a significant portion of the power is reactive power, which can lead to inefficiencies. This is because the current required to deliver the real power is higher when the tehonottotekijä is low. This increased current can cause greater resistive losses in wires and transformers, leading to higher energy consumption and potentially requiring larger, more expensive electrical equipment.

In industrial and commercial settings, utilities often penalize customers with low tehonottotekijät through higher electricity bills. This is because the utility must supply the total apparent power, even if only a portion is being used effectively by the customer. Therefore, maintaining a good tehonottotekijä is important for economic reasons and for improving the overall efficiency of the electrical grid. Common causes of low tehonottotekijä include inductive loads like electric motors and fluorescent lighting. These can be corrected by installing power factor correction equipment, such as capacitors, which introduce leading reactive power to counteract the lagging reactive power of inductive loads.