Electric current - High voltage power lines buzzing

[alicia113]

Electric current -- High voltage power lines buzzing

Question:

High voltage power lines string along roads often give off a faint buzzing sound. Use what you know about the motor principle to explain the source buzzing.




ok, so i have no idea how to approach this. I've never heard the buzzing around high voltage lines, but i am guessing it has something to do with the metal around it? i don't really know can someone please help me !

 

[truesearch]

do you know how an electric motor works... current in a wire in a magnetic field moves !
Power cables have AC current flowing in them, The current creates magnetic fields,... does this give any clues?

 

[alicia113]

do you know how an electric motor works... current in a wire in a magnetic field moves !
Power cables have AC current flowing in them, The current creates magnetic fields,... does this give any clues?

Unfortunately no :( ok in going to take a guess here the current moves on way and the electro magnetic field hits other wires causing them to vibrate ?

 

[berkeman]

Question:

High voltage power lines string along roads often give off a faint buzzing sound. Use what you know about the motor principle to explain the source buzzing.




ok, so i have no idea how to approach this. I've never heard the buzzing around high voltage lines, but i am guessing it has something to do with the metal around it? i don't really know can someone please help me !

Unfortunately no :( ok in going to take a guess here the current moves on way and the electro magnetic field hits other wires causing them to vibrate ?

You are close to correct in your guess, at least with the question worded the way it is. There can be two sources of noise from HV powerlines -- the electromechanical effect that you are trying to describe, and a more common one that is more apparent in wet weather:

http://en.wikipedia.org/wiki/Corona_discharge

To better describe the electromechanical effect, does your textbook describe the Lorentz force at all? How about the forces between parallel wires carrying currents?

 

[alicia113]

Nope nothing It's out home summer school course and each unit/lesson is about 6 to 7 pages of information so there's nothing on it

 

[berkeman]

Nope nothing It's out home summer school course and each unit/lesson is about 6 to 7 pages of information so there's nothing on it

What level in school is this? Is it high school or first year college? Have you had trig? How much calculus have you had?

The wikipedia page on the Lorentz force has several levels of math explanations...

http://en.wikipedia.org/wiki/Lorentz_force

(and scroll down to the section on "Force on a current carrying wire"...)

 

[NascentOxygen]

Question:

High voltage power lines string along roads often give off a faint buzzing sound. Use what you know about the motor principle to explain the source buzzing.

Hmmm^‡, I´d never thought of the motor principal being involved in power line hum, not even in a tiny way. It would be interesting to determine whether the contribution by this means is discernible.

Though the premise itself is sound^*.



‡ no pun intended
* ditto[/size]

 

[alicia113]

What level in school is this? Is it high school or first year college? Have you had trig? How much calculus have you had?

The wikipedia page on the Lorentz force has several levels of math explanations...

http://en.wikipedia.org/wiki/Lorentz_force

(and scroll down to the section on "Force on a current carrying wire"...)

High school grade 11. It is an at home physics course so I'm teaching myself. So it's hard. And ok will do. I'll check it out and post later what I get!

 

[alicia113]

Hmmm^‡, I´d never thought of the motor principal being involved in power line hum, not even in a tiny way. It would be interesting to determine whether the contribution by this means is discernible.

Though the premise itself is sound^*.



‡ no pun intended
* ditto[/size]

do you think what i said earlier would be correct in some ways?

 

[NascentOxygen]

do you think what i said earlier would be correct in some ways?

Sure.

Are you getting close to being able to answer the question in your post #1 here?

Perhaps you are not sure what is meant by the motor principle? Well, it relates to wires carrying electric current. If these conductors are near each other, the magnetic field around each will cause an attraction (or maybe repulsion) by the other.