What is the graphical method to construct phasor diagrams

[jbjaidee]

They are asking me to construct phasor diagrams for some separate problems using the graphical method for e,f, and g. What does that mean?

Thanks

 

[Dr.Peterson]

They are asking me to construct phasor diagrams for some separate problems using the graphical method for e,f, and g. What does that mean?

Thanks

Please show the entire problem. I presume e, f, and g are parts of it, so there's no way to answer you without knowing what you are being asked to do, specifically.

Do you know what a phasor diagram is? If not, have you done a search (or do you have a textbook you can refer to)? Here is one source: https://www.electronics-tutorials.ws/accircuits/phasors.html .

 

[jbjaidee]

Here is the question:

On a separate sheet of paper, construct the phasor diagrams for the following problems using a scale of 1cm=10 units. Use graphical method for e, f, and g.

A. 50∠25° + 65∠55°

B. 75∠140° - 55∠-20°

And yes I do know what phasors are. I just haven't done the math in a long time and need some extra help. Thanks

 

[Deleted member 4993]

Here is the question:

On a separate sheet of paper, construct the phasor diagrams for the following problems using a scale of 1cm=10 units. Use graphical method for e, f, and g.

A. 50∠25° + 65∠55°

i) Draw a line from the origin at 25^o (counter-clockwise) from x⁺-axis. Draw a point (P) on the line 5 cm [first quadrant] away from the origin. [edited]

ii) Draw a line from the origin at 55^o from x⁺-axis (counter-clockwise). Draw a point (Q) on the line 6.5 cm [first quadrant] away from the origin. [edited]

continue....

B. 75∠140° - 55∠-20°

And yes I do know what phasors are. I just haven't done the math in a long time and need some extra help. Thanks

.
I still do not know what is "meant" by e,f and g.

 

[Dr.Peterson]

Here is the question:

On a separate sheet of paper, construct the phasor diagrams for the following problems using a scale of 1cm=10 units. Use graphical method for e, f, and g.

A. 50∠25° + 65∠55°

B. 75∠140° - 55∠-20°

And yes I do know what phasors are. I just haven't done the math in a long time and need some extra help. Thanks

The reason I asked if you know what phasors are is that this question primarily involves drawing a picture of that meaning. This is not "math" in the sense of a calculation! If your difficulty is in the actual drawing, you may need to send a picture of your work.

Draw an arrow from the origin at angle 25° from the positive x-axis, with a length of 50 units (i.e. 5 cm). Then, depending on how you have been taught to do it, either draw another arrow at the origin with angle 55° and length 65, and make a parallelogram; or draw that arrow starting at the end of the first one, and then connect the origin to the end of the second arrow.

The link I gave last time shows the first method, under Phasor Addition.

Subtraction can be done a couple ways, one of which is to change it to an addition: 75∠140° + 55∠20°.

I forget if you said you have a source you are using to review this topic, as opposed to a mere source of questions; it should show all these things, so I should just be helping you with specifics (like what you did wrong in a particular answer). It's really helpful when you can show your wrong answers, and explain your thinking, so that we have as much as possible to work with.

 

[mmm4444bot]

I still do not know what is "meant" by e,f and g.

I'm thinking there is more than one method taught (to work with phasors) and the instruction specifies to use a "graphical" method in exercises (e), (f), and (g).

However, it seems jbjaidee is starting with exercises (a) and (b), so maybe we'll get into the specific graphical method, later. :cool:

 

[Dr.Peterson]

I'm thinking there is more than one method taught (to draw 'em) and the instruction specifies to use the "graphical" method in exercises (e), (f), and (g).

However, it seems jbjaidee is starting with exercises (a) and (b), so maybe we'll get into the graphical method, later. :cool:

jbjaidee, please state the entire problem as given to you, including all parts and instructions! We are getting confused.

Your question was about constructing phasor diagrams "using the graphical method" for e,f, and g; but you are giving us parts a and b, for which you haven't stated instructions. Are you, or are you not, expected to do those graphically? (I can't imagine how you can draw a diagram without doing so graphically ...) Seeing the whole thing should clear this up.

 

[jbjaidee]

Those are all the instructions I have. If there is no math involved, I guess I just draw them on some graphing paper.

I thought someone would know what e,f, and g might be.

This is a correspondence course I am doing for protective relaying. So my resources are somewhat slim.

Thanks

 

[Dr.Peterson]

Those are all the instructions I have. If there is no math involved, I guess I just draw them on some graphing paper.

I thought someone would know what e,f, and g might be.

This is a correspondence course I am doing for protective relaying. So my resources are somewhat slim.

Thanks

You mean you've told us the entire problem, and there are no parts e, f, and g following your parts a and b, as we've been expecting? The problem is exactly this, and no more?

On a separate sheet of paper, construct the phasor diagrams for the following problems using a scale of 1cm=10 units. Use graphical method for e, f, and g.

A. 50∠25° + 65∠55°

B. 75∠140° - 55∠-20°
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If e, f, and g are not part of the problem, then they must be something previously referred to! Do they perhaps have some previous diagrams representing, say "e + f = g", so that they are (in their own usage) taking g to mean the resultant of e and f? That's the only interpretation I can think of.

If you can't see an example you were given that shows what they mean, could you send us an image of something relevant, such as an example with similar instructions?

But as far as I can tell, they are just saying to make a drawing of these phasor sums.