PE Power #13

[yaoyaodes]

Can anyone help me explain this question? My answer was D, not quite sure how the capacitor impact the circuit.

 

[akyip]

This problem is a bit hard to explain. I tend to have a more difficult time explaining power electronics. Attached is my work and notes for this problem (this was problem 113 in the previous version of the NCEES PE Power practice exam).

 

[akyip]

Also attached are some notes and information I have about the capacitor and charging current in a rectifier circuit. I learned this from Zach Stone's Electrical PE Review.

• Remember from circuit fundamentals that a capacitor is able to hold/store a voltage. So when the input or source AC voltage cycles between positive and negative, the capacitor stores some of that voltage. More specifically, the capacitor cycles between charging up and discharging.
• The capacitor charges up when the input voltage is greater than or equal to the capacitor voltage. So there is charging current flowing into the capacitor during this time.
• The capacitor discharges once the input voltage is less than the capacitor voltage. So as it discharges, the charging current leaves the capacitor.

 

[Zach Stone P.E.]

Also attached are some notes and information I have about the capacitor and charging current in a rectifier circuit. I learned this from Zach Stone's Electrical PE Review.

• Remember from circuit fundamentals that a capacitor is able to hold/store a voltage. So when the input or source AC voltage cycles between positive and negative, the capacitor stores some of that voltage. More specifically, the capacitor cycles between charging up and discharging.
• The capacitor charges up when the input voltage is greater than or equal to the capacitor voltage. So there is charging current flowing into the capacitor during this time.
• The capacitor discharges once the input voltage is less than the capacitor voltage. So as it discharges, the charging current leaves the capacitor.

Thanks for the mention @akyip!

 

[yaoyaodes]

This problem is a bit hard to explain. I tend to have a more difficult time explaining power electronics. Attached is my work and notes for this problem (this was problem 113 in the previous version of the NCEES PE Power practice exam).

Thank you! I am sorry, I could not read. The image is not so clear. is that possible that you can take another photo?

 

[akyip]

Thank you! I am sorry, I could not read. The image is not so clear. is that possible that you can take another photo?

You can download visible attachments and then open them up separately and zoom in on them further if needed... Does this not work for you?

 

[no_concentrate]

Thanks for a good explanation but to clear my doubts further I want to read the attachment but even after downloading and I open in further I am not able to read.

 

[no_concentrate]

You can download visible attachments and then open them up separately and zoom in on them further if needed... Does this not work for you?

Thanks for a good explanation but to clear my doubts further I want to read the attachment but even after downloading and I open in further I am not able to read.

 

[Sam.Gov]

If the neutral lead is connected to the rectifier why is the charging current negative and the correct answer is not graph B?

Please see the attached photo for what I mean.

Any help is appreciated.

 

[Zach Stone P.E.]

If the neutral lead is connected to the rectifier why is the charging current negative and the correct answer is not graph B?

Please see the attached photo for what I mean.

Any help is appreciated.

There is a much more in-depth discussion on this problem here:

https://community.electricalpereview.com/c/third-party-practice-exams/ncees-13

 

[Sam.Gov]

There is a much more in-depth discussion on this problem here:

https://community.electricalpereview.com/c/third-party-practice-exams/ncees-13

Thank you