Harmonics

[Steve100]

We had the following question for homework the other day and I think the answer is 'C' (reg 523.6.3) but my mate thinks its 'A', does anybody k ow the correct answer?

In a TP & N installation servicing an office with IT equipment and a high harmonic disturbance. How would the harmonic influence be combated?

A. Surge protection

B. Insulation of live parts

C. Increase the size of the neutral

D. Install an RCD

Thx

 

[steptoe]

wells its deffo not A 

why do you think increasing the N size will change anything?

as you may already have noticed, no-one here will give you answers to homework Qs, merely try and point you.

 

[steptoe]

Your mates wrong

Can I answer ?

NO

 

[kerching]

I used to like the Harmonics on the begining of The Old Grey Whistle Test [probably not even an harmonica!   But WTF any excuse for a good tune.......]

https://www.youtube.com/embed/FfKWPyj51vU?feature=oembed

 

[Marvo]

.......I think the answer is 'C'...

Why would you believe your mate when you have your answer with a regulation to back it up?

 

[binky]

As with Steps, I won't give you and answer, but will suggest eradicating what are the wrong answers. For instance surge protection is designed to protect agaianst surges from the national gird / lighting, so defo isn't going to improve a situation within a building as desribed.

feel free to post your thoughts and logical reasonings on here (don't necessarrily expect a logical reply :^O ) and we will do our best to guide you through the problem. That way you will learn something

 

[Steve100]

Well it was more that I disagreed with my mate when we where discussing the question. In addission the lecture said the correct answer was 'A'. My logic for 'C' was that 'A' protects against surge voltages, an RCD protects against shock by detecting inbalance in the line and neutral and insulation of live part is basic protection. Also according to reg 523.6.3 increasing the neutral CSA will help reduce the effects of harmonics.

 

[Sidewinder]

Ask your lecturer to contact us through here and we will explain the errors of his teaching methods with regulations and fundamental science!

 

[kerching]

Mmmm....sounds like a bit of a dodget to me...could this be why he is a Lecturer

there is always option e)....report it to your Supervisor          :slap       

 

[Manator]

Ask your lecturer to contact us through here and we will explain the errors of his teaching methods with regulations and fundamental science!

I agree, the question here is down to the third harmonic, which can be combatted with the increase in the neutral conductor to take the excess loads. I fail to understand why any lecturer would not understand the basics? Is there now a fast track course for them as well?

 

[revjames]

Stick with http://www.google.co.uk/imgres?num=10&hl=en&tbo=d&biw=1366&bih=619&tbm=isch&tbnid=1a7TWPYQ8MoBLM:&imgrefurl=http://www.musicwithease.com/harmonica-pictures.html&docid=pe3YYAla1m2juM&imgurl=http://www.musicwithease.com/harmonica-1.gif&w=528&h=318&ei=2CG7UPfrDIzP0AW41oHIDA&zoom=1&iact=hc&vpx=607&vpy=171&dur=164&hovh=174&hovw=289&tx=186&ty=64&sig=114426966925507941213&page=1&tbnh=135&tbnw=224&start=0&ndsp=18&ved=1t:429,r:3,s:0,i:159'> this

 

[kerching]

I covertly recorded this on my iphone at the last TEF Pub Quiz Night.....featuring 2 forum members who shall remain nameless

https://www.youtube.com/embed/bI6wZNBLOY0?feature=oembed

 

[binky]

c gets my vote, would be interesting to know how your lecturer reckons surge protection helps.

 

[Doc Hudson]

For many years, it has been a common feature of C&G sample papers, used by colleges for setting homework, to have one or two incorrectly written, or incorrectly answered questions. I suspect your lecturer has a printed sheet with the questions and another one with a list of answers. But unfortunately maybe they do not have a clue how to explain, verify or confirm how any of the answers are attained. Just blindly reading question 5 is A, question 6 is D etc.

Doc H.

 

[binky]

good point C&G have always been full of errors

 

[wozz]

I agree, the question here is down to the third harmonic, which can be combatted with the increase in the neutral conductor to take the excess loads. I fail to understand why any lecturer would not understand the basics? Is there now a fast track course for them as well?

is combatted the correct term, you havnt combatted it have you? you have increased a conductor size to handle the effects of it.  combatting I would have thought would be actually reducing/stopping the harmonic current itself?

am I barking up the right tree?

 

[binky]

meow

think you're getting to predantic with wordings, though combatted isn't good terminology :^O