Power Factor and Phasor Diagram

AI Thread Summary
Power factor is calculated as the cosine of the phase angle, which is determined using the formula Tan Inverse((XL - Xc) / R). In a phasor diagram where inductive reactance (XL) exceeds capacitive reactance (Xc), the voltage is represented as a horizontal line to the right, while the current is depicted as a line at an angle downwards from the voltage line. The discussion emphasizes that reactances combine to yield a total reactance, indicating whether a system is capacitive or inductive. It is noted that if specific values are not provided, the described phasor diagram remains accurate. Understanding the basics of inductive and capacitive circuits is essential for clarity in these concepts.
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OK, Hello!

Have to make sure as I felt like I knew my stuff but failed my first exam, am I on the right tracks?

Power Factor = Cosine of phase angle

Phase angle = Tan Inverse ((XL-Xc)/R)

(So you know)
XL= Inductive Reactance
Xc= Capacitive Reactance
R = Resisstance

Am I right so far?

And for the phasor diagram, since in this case XL > Xc it would be illustrated as a horizontal line going towards the right, marked as Voltage, and a second line would go from the origin of the Voltage line downwards at an angle which would be the Phase angle, this second line illustrating the Current. Is that all I would have to do if I was told to draw a phasor diagram?

Is all this correct? My confidence has been wounded :(,,! I must make sure!, so please help if you can!
 
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Those equations are correct, even if they do look a little different from the standard ones.

Generally reactances sum to give a total reactance, so the outcome is either a capacitive system or an inductive system, rather than saying that there is more inductance than capacitance. Same result though.

If you aren't given numbers, then that phasor diagram would be accurate.

It may also help to keep the acronym 'CIVIL' in mind, as per the diagram attached.
 

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Thank you Zryn. Nice to know I'm on the right tracks. Will remember CIVIL, it will be very useful. And will also bare in mind about inductive and capacitive circuits. I'm sure if I knew the basics about Xc and XL circuits that what you said would be obvious so will have to work on that.
James
 

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