How to draw phasor diagrams?

Answer 1

1) (ex: for 360 degree--->10 cm on the paper).

2) Draw simple sinusoidale wave.

3) This wave has a period of 2*pi in rad or 360 in degree (it's a multiple of 2*pi in fact).

4) The next wave will be 120 degree distant from the first wave.

5) So you move 120 degree (or 10/3 cm) from the first starting point (having amplitude=0) of the first wave.

6) Draw the starting point (having amplitude=0) of the second wave at the distance mentioned in 5).

7) Then starting from the point in 6) draw the second wave similar to the first wave.

8) Same procedure for drawing the third wave (repeate procedure 4 till 7 but switch the first wave with the second and the second with the third).

9) The formulas are:

10) In fact when x=pi/2-----------> VL1=Vp=|Vmax|

x=pi/2 +2pi/3--> VL2=Vp=|Vmax|

Answer 2

Consider sine waves for

e.g sin 120+240j (sin A+Dj)

where

A - magnitude

D - angle or radians

j - sqrt (-1)

then draw the 2 dimensional graph

by using the above conditions

Answer

For a series circuit, the current is the reference phasor which should lie along the positive horizontal axis. Next, draw the voltage drop across the resistive component (UR) parallel with the reference phasor. Next draw the voltage drop(s) across the inductive and/or capacitive components (UL and/or UC) lagging/leading the reference phasor. Finally, vectorially add the voltage drops to determine the supply voltage.

For a parallel circuit, the supply voltage is the reference phasor which should lie along the positive horizontal axis. Next, draw the current through the resistive branch (IR) parallel with the reference phasor. Next draw the currents(s) through the inductive and/or capacitive branches (IL and/or IC) leading/lagging the reference phasor. Finally, vectorially add the currents to determine the supply current.

For a three-phase system, start by drawing the phase voltages, then draw the line voltages by vectorially-adding the phase voltages.

Answer 3

First take the suitable reference as either current or voltage. Then track on voltage drops.

Follow the standard notations. You should be clear in lagging and leading concepts.