Ques. What is the physical meaning of this?
Ans. In an actual alternator, of which fig. 1,288 is an elementary diagram showing one coil, if the current lag, say 45° behind the pressure, it means that the coil rotates 45° from its position of zero induction before the current starts, as in fig. 1,288.
EXAMPLE I.—A circuit through which an alternating current is passing has an inductance of 6 ohms and a resistance of 2.5 ohms. What is the angle of lag?
Fig. 1,291.—Diagram of circuit for example I.
Substituting these values in equation (1), page [1,053],
| 6 | ||||
| tan φ | = | = | 2.4 | |
| 2.5 |
Referring to the table of natural sines and tangents on page 451 the corresponding angle is approximately 67°.
EXAMPLE II.—A circuit has a resistance of 2.3 ohms and an inductance of .0034 henry. If an alternating current having a frequency of 125 pass through it, what is the angle of lag?
