The amplitude of these vibrations depends on the flux density in the laminations and the magnetic properties of the core steel, and is therefore independent of the load current. Debraj Chatterjee Aug 15, This part of IEC defines sound pressure and sound intensity measurement methods by which sound power levels of transformers, reactors and their associated cooling auxiliaries may be determined. Leave a Comment Click here to cancel reply. This standard is primarily intended to apply to measurements made at the factory. Professional in AutoCAD programming.
| Uploader: | Bralrajas |
| Date Added: | 7 July 2010 |
| File Size: | 46.17 Mb |
| Operating Systems: | Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X |
| Downloads: | 40992 |
| Price: | Free* [*Free Regsitration Required] |
The perceived loudness of a signal is dependent upon the sensitivity of the human ear to its frequency spectrum.
IEC | IEC Webstore
Facebook Linkedin Linkedin Twitter. Sources of sound The audible sound radiated by transformers is generated by a combination of magnetostrictive deformation of the pddf and electromagnetic forces in the windings, tank walls and magnetic shields. We notice people using both words such as noise and sound while referring to Transformer Humming. Sound power is the parameter which is used for rating and comparing sound sources. The content is copyrighted to EEP and may not be reproduced on other websites.
This has resulted in a number of internationally standardized weightings of which the Aweighting network is the most common.
In addition, stray magnetic fields may induce vibrations in structural components. Recent advances in core designcombined with the use of low induction levels, have reduced the amount of sound generated in the core such that the sound caused by the electromagnetic forces may become significant.
The force and therefore the amplitude of the vibrations is proportional to the square of the current, and the radiated sound power is proportional to the square of the pd amplitude.
Dry-type power transformers
Any associated kec equipment will also generate noise when operating. Sound intensity measurements have the following advantages over sound pressure measurements: Consequently, the radiated sound power is strongly dependent on the load current.
An intensity meter responds only to the propagating part of a sound field and ignores any non-propagating part, for example, standing waves and reflections; The intensity method reduces the influence of external sound sources, as long as their sound level is approximately constant.
Premium Membership Premium membership gives you an access to specialized technical articles and extra premium content electrical guides and software.
Debraj Chatterjee Aug 15, To be specific would any one give clarity over this please!
The amplitude of these vibrations depends on the flux density in the laminations and the magnetic properties of pdd core steel, and is therefore independent of the load current. Professional in AutoCAD programming. Related EEP's content with sponsored links.
IEC 60726:1982/Amd.1:1986
Vibrations in core and winding assemblies can then induce sympathetic vibrations in tank walls, magnetic shields and air ducts if present. This is the reference level 0 dB to which all the other levels are compared.
The audible sound radiated by transformers is generated by a combination pf magnetostrictive deformation of the core and electromagnetic forces in the windings, tank walls and magnetic shields. Current flowing in the winding conductors produces electromagnetic forces in the windings.
Sound intensity is defined as the rate of energy flow per unit area and is measured in watts per square metre. Leave a Comment Click here to cancel reply.
This standard is primarily intended to apply to measurements made at the factory. Subscribe to Weekly Digest Get email alert whenever we publish new electrical guides and articles.
This part of IEC defines sound pressure and sound intensity measurement methods by which sound power levels of transformers, reactors and their associated cooling auxiliaries may be determined.
IEC /Amd in English | Download PDF |
Modern measuring instruments process sound signals through electronic networks, the sensitivity of which varies with frequency in a manner similar to the human ear. After prolonged search and research it is confirmed Noise word is used in description of humming of transformers and levels of disturbance measuring as well in db pertaining to noise—.
It is a vector quantity whereas, sound pressure is a scalar quantity and is defined only by its magnitude.
Комментарии
Отправить комментарий