why does high tension wires produce humming sound ?

Asked by Last Modified  

4 Answers

Learn Class IX-X Tuition

Follow 0
Answer

Please enter your answer

Satyendra Shukla

Perl Developer | Perl Trainer

The reason for this is something known as "magnetostriction", which is strain induced in a magnetic lattice due to the magnetic nature of a material. There is a pretty good explanation of the buzzing noises in transformers here, but the summary is that the ferromagnetic domains in the transformer core...
read more
The reason for this is something known as "magnetostriction", which is strain induced in a magnetic lattice due to the magnetic nature of a material. There is a pretty good explanation of the buzzing noises in transformers here, but the summary is that the ferromagnetic domains in the transformer core are subjected to the 60Hz (in the US) oscillations of the magnetic field due to the AC current. Because of the electrical cycle, there are two impacts on the core per AC oscillation, so the strain is changing at 60 Hz, which produces the 120 Hz noise that we can identify a "great B" note. read less
Comments
Dislike Bookmark

"The audible noise emitted from high-voltage lines is caused by the discharge of energy that occurs when the electrical field strength on the conductor surface is greater than the 'breakdown strength' (the field intensity necessary to start a flow of electric current) of the air surrounding the conductor....
read more
"The audible noise emitted from high-voltage lines is caused by the discharge of energy that occurs when the electrical field strength on the conductor surface is greater than the 'breakdown strength' (the field intensity necessary to start a flow of electric current) of the air surrounding the conductor. This discharge is also responsible for radio noise, a visible glow of light near the conductor, an energy loss known as corona loss and other phenomena associated with high-voltage lines. read less
Comments
Dislike Bookmark

The audible noise emitted from high-voltage lines is caused by the discharge of energy that occurs when the electrical field strength on the conductor surface is greater than the 'breakdown strength' (the field intensity necessary to start a flow of electric current) of the air surrounding the conductor....
read more
The audible noise emitted from high-voltage lines is caused by the discharge of energy that occurs when the electrical field strength on the conductor surface is greater than the 'breakdown strength' (the field intensity necessary to start a flow of electric current) of the air surrounding the conductor. This discharge is also responsible for radio noise, a visible glow of light near the conductor, an energy loss known as corona loss and other phenomena associated with high-voltage lines. "The degree or intensity of the corona discharge and the resulting audible noise are affected by the condition of the air--that is, by humidity, air density, wind and water in the form of rain, drizzle and fog. Water increases the conductivity of the air and so increases the intensity of the discharge. Also, irregularities on the conductor surface, such as nicks or sharp points and airborne contaminants, can increase the corona activity. Aging or weathering of the conductor surface generally reduces the significance of these factors. "The higher voltages at which modern transmission lines operate have increased the noise problem to the point to which they have become a concern to the power industry. Consequently, these lines are now designed, constructed and maintained so that during dry conditions they will operate below the corona-inception voltage, meaning that the line will generate a minimum of corona-related noise. In foul weather conditions, however, corona discharges can be produced by water droplets, fog and snow." read less
Comments
Dislike Bookmark

Two reasons: One is coronal discharge. The high voltage between adjacent wires (phases) is enough to make air conduct. As the voltage between phases is alternating, and constantly changing, the sound changes. Second reason: Current through the wire isn't fixed. The varying current causes expansion...
read more
Two reasons: One is coronal discharge. The high voltage between adjacent wires (phases) is enough to make air conduct. As the voltage between phases is alternating, and constantly changing, the sound changes. Second reason: Current through the wire isn't fixed. The varying current causes expansion and contraction of the wire, producing sound. Especially of concern is power factor far from 1, with current much higher at the peaks. Most electrical transmission is done three phase. So at 120 Hz and 120 degrees apart, each wire will expand slightly, creating a click, and the effective frequency might be as high as 480 Hz, explaining why it might sound higher in pitch. read less
Comments
Dislike Bookmark

View 2 more Answers

Related Questions

In a class test, the sum of marks obtained by P in Mathematics and Science is 28. Had he got 3 more marks in Mathematics and 4 marks less in Science, the product of marks obtained in the two subjects would have been 180? Find the marks obtained in two subjects separately.
Let the marks of mathematics be x Than marks of science be 28-x now according to question (x+3), (28-x-4) The product of new marks will be 180 So, (x+3) (28-x-4)=180 24x-x^2+72-3x=180 x^2-21x+108=0 x^2-12x-9x+108=0 x(x-12)-9(x-12)=0 (x-9)(x-12)=0 (x-9)=0...
Sanjay
0 0
7
What is sustainable development?
Sustainable development is the development of the society to meet the human development goals, and without compromising on the need to balance the ecosystem and the environment. It is essential to maintain...
Shiva
If the roots ff the equation (c2 – ab)x2 – 2(a2 – bc)x + b2 – ac = 0 are equal, then prove that either a = 0 or a3 + b3 + c3 = 3abc"
u can do this problem with the help of SHIDHARACHARYA formula which is ax2=bx+c=0
Isha
0 0
5
What is the full form of CNG?
Compressed Natural Gas
Keerthi
0 0
5
How much is the hourly charge for Maths home/online tuition for IGCSE/IB 8th to 12th grade?
Rs 200
Prasad Kaggallu

Now ask question in any of the 1000+ Categories, and get Answers from Tutors and Trainers on UrbanPro.com

Ask a Question

Related Lessons

Protein
Proteins are organic molecules consisting of many amino acids bonded together. Amino Acids: Monomers or building blocks of all proteins. Parts of the Amino Acid: a) Amino group (NH2) b) Carboxyl...

Bhakti M.

0 0
0
To Improve Or Build Up Your Vocabulary.
One of the best ways to improve or build up vocabulary is to write or use one-word substitutes for the given phrase. It is very important to write precisely and speak in a single word. Like the word...

Vijayasree

5 0
0
Probability
Probability is the possibility of an event to be occurred or happened. Probability is the ratio of the number of favorable events with the total number of events. An event which is definitely...
M

Mohit S.

1 0
0
Turbine & Power
An open cycle gas turbine works on (A) Otto cycle (B) Carnot cycle (C) Joule's cycle (D) Stirling cycle Correct Answer Which of the following has the highest calorific value? (A) Anthracite coal (B)...

Rahul Kumar

1 0
0
Reflection Of Light (Questions)
Reflection of Light Rays on a Reflecting Surface: When a light ray strikes a surface separating two media with different optical properties, part of the light energy is reflected back to the media where...

Soumi R.

2 0
0

Recommended Articles

Meet Swati, a Hindi Tutor from Bangalore

Swati is a renowned Hindi tutor with 7 years of experience in teaching. She conducts classes for various students ranging from class 6- class 12 and also BA students. Having pursued her education at Madras University where she did her Masters in Hindi, Swati knows her way around students. She believes that each student...

Read full article >

Quest Academy - Institute of the month

Quest Academy is a professional Bangalore based NEET and JEE (Main + Advanced) training institute. The academy was incorporated in 2015 to cater to the needs of students, who aim to crack competitive exams by connecting with the best brains around. The institute helps students enhance their skills and capabilities through...

Read full article >

Meet Raghunandan.G.H, a B. Tech Tutor from...

Raghunandan is a passionate teacher with a decade of teaching experience. Being a skilled trainer with extensive knowledge, he provides high-quality BTech, Class 10 and Class 12 tuition classes. His methods of teaching with real-time examples makes difficult topics simple to understand. He explains every concept in-detail...

Read full article >

Meet Sandhya R, a B.Sc tutor from Bangalore

Sandhya is a proactive educationalist. She conducts classes for CBSE, PUC, ICSE, I.B. and IGCSE. Having a 6-year experience in teaching, she connects with her students and provides tutoring as per their understanding. She mentors her students personally and strives them to achieve their goals with ease. Being an enthusiastic...

Read full article >

Find Class 10 Tuition near you
Class 10 Tuition in Delhi
Class 10 Tuition in Bangalore
Class 10 Tuition in Hyderabad
Class 10 Tuition in Kolkata
Class 10 Tuition in Mumbai
Class 10 Tuition in Chennai
Class 10 Tuition in Pune
Class 10 Tuition in Noida
Class 10 Tuition in Lucknow
Class 10 Tuition in Gurgaon
Online Tuition Class 10

Looking for Class 10 Tuition ?

Learn from the Best Tutors on UrbanPro

Are you a Tutor or Training Institute?

Join UrbanPro Today to find students near you