${\displaystyle \delta =\text{a}\text{r}\text{c}\text{t}\text{a}\text{n}\frac{R}{\left|X\right|}}$

Note 1 to entry: The loss angle is defined in 151-15-48 as the angle the tangent of which is the dissipation factor, or ratio of active power to the absolute value of reactive power. Other loss angles are defined in electromagnetism (see 121-12-17 and 121-12-35).