Transformer noise - Ways to troubleshoot

Transformer noise - what is transformer noise and ways to troubleshoot

The transformer noise phenomenon is of particular concern recently, because the more power the transformer increases, the louder the noise it creates. On the other hand, nowadays there is a tendency to place transformers near residential areas to supply electricity for big cities, or to place transformers in factories. Therefore, it is necessary to find a way to minimize the noise generated by the transformer when operating.


Table of contents

1. The cause of the transformer noise

2. Working principle of the transformer noise

3. Measures to reduce the noise of the transformer


1. The cause of the transformer noise

The main cause of a transformer noise when operating is magnetostriction in its steel core. When magnetized with alternating currents, the sheet is periodically stretched or contracted with a frequency twice that of the grid current and an amplitude of a few microns per meter. For example, a power source with a frequency of 100Hz will cause noise or vibration with a specific frequency of 200Hz.


The current flowing through the windings also generates pulsating forces in the axial and radial direction, but the amplitude is weak and produces little noise.


Cooling equipment such as blowers and pumps also generates additional motion noise.


Also due to the transformer installation, the oscillation of the transformer will propagate down to the foundation and can cause resonance with neighboring metal structures.


2. Working principle of the noise in the transformer

Transformer noise travels from the steel core to the housing directly or indirectly via oil and dielectric. In their turn, the oil tank and radiator fins make a sound to their surroundings.


Video about noise in transformers:



Related article: the difference between step up and stepdown transformer

3. Measures to reduce the noise of the transformer

The first measure involves sheets of transformer steel cores by:

  • Use cold rolled steel with low magnetism

  • The steel core joint is inclined, ensuring even flux distribution

  • Look for a uniform steel core

  • Exclude holes in the steel core

  • Squeeze the steel core with plastic and glass belts

The sound travels from the steel core to the shell, so trying to squeeze parts can cause vibrations. Reduces sound transfer from the steel core to the housing by using dampers and coating the inside of the oil tank with an acoustic seal.


Among the accessories, the blower makes a significant noise, so use a low-speed fan of 750 rpm, select the appropriate blade type. 


In addition to the above measures, they also use sound-canceling screens placed on one or more sides or enclosing the transformer. If you block the transformer with a concrete wall near the transformer, sound waves generated by the transformer will be refracted and attenuated. The wall should be high enough and wide enough.


Related article: 

difference between stepup and stepdown transformer

what is power transformer


MBT's transformer has overcome the maximum noise errors during the transformer operation. The meticulous steel core grafting process ensures that the machine works smoothly, gently, and reduces noise. MBT's accessories are also researched, selected and used in the most appropriate way so that MBT's transformer products can meet all demanding requirements of customers.

Contact +84 913 006 538 for a free consultation and receive the most preferential quotation.


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