
Phasors 221
Example 9 Add 20 7150° and 40 /120°.
20 cos 150° + j 20 sin 150° = -17.3 + ;10
40 cos 120° + / 40 sin 120° = -20 + ;34.64
-17.3 + ylO - 20 + y34.64
= -37.3
-I-
;44.64
44 64
=
V(-37.3
2
+ 44.64
2
) 180 + tan"
1
——
-37.3
= 58.17 7129.89°
(See program 188, page 220.)
Example 10 Add 20 /-100° and 40 /-140°.
20 cos - 100° + j 20 sin - 100° = -3.47 - ;19.7
40 cos - 140° + / 40 sin - 140° = -30.64 - ;25.7
-3.47 - ;19.7 - 30.64 - p5J
= -34.11 - ;45.4
-45 4
=
V[-34.11
2
+ (-45.4)
2
] tan'
1
' - 180
= 56.78 7-126.92°
(See program 188, page 220.)
Example 11 Add 10
7-45°
and 15 7-30°
10 cos - 45° + j 10 sin - 45° = 7.07 - p.07
15 cos - 30° + j 15 si ...