What causes the humming sound in transformers?

  • Context: High School 
  • Thread starter Thread starter woollymac
  • Start date Start date
  • Tags Tags
    Transformers
Click For Summary
SUMMARY

The humming sound in transformers is primarily caused by magnetostriction in the iron core, which leads to vibrations as the coils carry alternating current (AC). This phenomenon occurs when the magnetic flux changes direction, resulting in the iron laminations altering their dimensions. The frequency of the hum is typically 120 Hz in North America and 100 Hz in other regions, corresponding to the AC cycles. The excitation level must exceed approximately 1 Tesla for significant magnetostriction to occur.

PREREQUISITES
  • Understanding of alternating current (AC) principles
  • Knowledge of magnetostriction and its effects on materials
  • Familiarity with transformer construction and operation
  • Basic concepts of magnetic flux and its behavior in electrical systems
NEXT STEPS
  • Research the effects of magnetostriction in different materials
  • Explore transformer design to minimize humming
  • Learn about the relationship between AC frequency and transformer operation
  • Investigate sound dampening techniques for electrical equipment
USEFUL FOR

Electrical engineers, transformer manufacturers, and anyone interested in the acoustic properties of electrical devices will benefit from this discussion.

woollymac
Messages
3
Reaction score
0
Why do transformers hum? Is it the iron core vibrating & if it is what is it that makes it vibrate? Is it the little atomic magnetics in the iron changing directions with the ac? Can anyone enlighten me?
 
Physics news on Phys.org
Basically I think you are right,the coils carry a.c.and this results in the core going through many magnetic cycles per second.The changing magnetic flux then results in vibrations.
 
Magnetostriction in the iron causes the iron laminations to change dimension when the excitation exceeds about 1 Tesla. Magnetostriction occurs twice per cycle, so the hum is 120 Hz (or 100 Hz) depending on where you live.
 

Similar threads

Undergrad What Causes the Einstein - de Haas Effect in Iron Rods?
  • · Replies 39 ·
2
Replies
39
Views
6K
High School Phase difference in a transformer
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Getting a reduced voltage from a fixed secondary voltage of a transformer
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad What Causes Induced EMF in Moving Conductors and Transformers?
  • · Replies 6 ·
Replies
6
Views
3K
High School Is the Transformer in My Adapter Damaged? A Question for Physics Assignment
  • · Replies 10 ·
Replies
10
Views
2K
Undergrad Short Circuiting the Secondary of a Transformer/Self Impedence
  • · Replies 17 ·
Replies
17
Views
4K
High School Transformer core saturation- is this core saturating?
  • · Replies 1 ·
Replies
1
Views
2K
High School Are silicon iron sheets really necessary for a commercial transformer?
  • · Replies 8 ·
Replies
8
Views
2K
High School What Determines Induced Voltage in a Transformer?
  • · Replies 4 ·
Replies
4
Views
2K
Graduate Why does a guitar string "beat" as if it is out of phase?
  • · Replies 11 ·
Replies
11
Views
3K