I am in Iraq and have a transformer question,everything done here has to be submitted to the Phillipines to a group of engineers supposedly familiar withthe NEC.In one of the comments referencing the submittal they are referencing a safety factor for the transformer,is this inthe NEC,I dont remember seeing it.I am aware of calculating transformer loads however a safety factor,not in the job specs,is new to me..Any ideas..Thanks from Anbar province..home away from home
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transformer
- Thread starter CAPTMIKE
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As a sales engineer for a dry type transformer manufacturer I have read plenty of specs and have never ran across the tern "safety factor."
The NEC has not interest in the transformer other than it is listed and labeled by a nationally recognized testing agency. Also the they are designed, built and tested per applicable IEEE/ANSI standards.
If the transformer meets UL requirements for example then it is applied and installed per the NEC requirements.
The NEC must be separated from the way a transformeris designed and built. If it is designed and labeled by a nationally recognized testing agency then the NEC alows it to be used.
Safety factor I would understand would be the responsibilty of the person who writes the specs for a transformer. One could consider loads, harmonics, ambient temperature, location, etc. One also considers transformer constuction such as the enclosure, temperature rise, insulation class, and many other things.
The NEC has not interest in the transformer other than it is listed and labeled by a nationally recognized testing agency. Also the they are designed, built and tested per applicable IEEE/ANSI standards.
If the transformer meets UL requirements for example then it is applied and installed per the NEC requirements.
The NEC must be separated from the way a transformeris designed and built. If it is designed and labeled by a nationally recognized testing agency then the NEC alows it to be used.
Safety factor I would understand would be the responsibilty of the person who writes the specs for a transformer. One could consider loads, harmonics, ambient temperature, location, etc. One also considers transformer constuction such as the enclosure, temperature rise, insulation class, and many other things.
transformers
transformers
Thanks for the great input,I had never heard of a "SAFETY FACTOR" either just wanted to get some extra input.I know what you mean about transformers like to run hot,heck look at their operating temperature.I have seen many electricians who like to touch things and make a determination of overloading by the temperature,tough on a transformer..
transformers
Thanks for the great input,I had never heard of a "SAFETY FACTOR" either just wanted to get some extra input.I know what you mean about transformers like to run hot,heck look at their operating temperature.I have seen many electricians who like to touch things and make a determination of overloading by the temperature,tough on a transformer..
Most transformers in the industrial commercial area don?t run anywhere near their capacity on a continual basis. Keeping the temperature rise down prolongs the life of the transformer,
But then there is the cost of operating the transformer. As such consideration must be made for loses at no load, 25%, 50%, 75% and 100% load in order to select the 150, 115, and 80 deg C temperature rises to determine which one will operate the most efficient at the average load that you would expect.
Heat can not only be detrimental to the life of the transformer but less heat generated represents less loss = higher efficiency.
Then it must be determined if the higher cost of a lower temperature rise will provide a payback in energy efficiency and/or longer transformer life.
But then there is the cost of operating the transformer. As such consideration must be made for loses at no load, 25%, 50%, 75% and 100% load in order to select the 150, 115, and 80 deg C temperature rises to determine which one will operate the most efficient at the average load that you would expect.
Heat can not only be detrimental to the life of the transformer but less heat generated represents less loss = higher efficiency.
Then it must be determined if the higher cost of a lower temperature rise will provide a payback in energy efficiency and/or longer transformer life.
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