480v distribution

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mstrlucky74

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Below is from a research paper I was reading. Question---if your distrusting 480v why do you need a transformer for a 277v piece of equipment. Thanks



Understand that it is much more efficient to distribute 480V than 120V. The later you derive 120V in the dis- tribution, the higher your efficiency will be. (Distribute at greater than 480V if you can specify a higher voltage service). Two other tips are:​
Use small 480-480/277V transformers to derive 277V as needed. Typical uses for 277V are lighting and HVAC reheat boxes (both available in 480V). Before specifying 480V, ensure the style you need is available in that voltage and you?ve addressed maintainability issues.
Use small (e.g., 15KVA) 480-120/208V transformers to derive 120V near the load, to shorten 120V runs. For a factory, think of 480/277V as feeding the infrastructure (e.g., HVAC, lighting, elevators, plant air) and produc- tion equipment and 208/120V as feeding controls and offices. For a commercial building, think of 480/277V as feeding the infrastructure, and 208/120V as feeding everything else.
 
mstrlucky74 said:
Below is from a research paper I was reading. Question---if your distrusting 480v why do you need a transformer for a 277v piece of equipment. Thanks



Understand that it is much more efficient to distribute 480V than 120V. The later you derive 120V in the dis- tribution, the higher your efficiency will be. (Distribute at greater than 480V if you can specify a higher voltage service). Two other tips are:​
Use small 480-480/277V transformers to derive 277V as needed. Typical uses for 277V are lighting and HVAC reheat boxes (both available in 480V). Before specifying 480V, ensure the style you need is available in that voltage and you?ve addressed maintainability issues.
Use small (e.g., 15KVA) 480-120/208V transformers to derive 120V near the load, to shorten 120V runs. For a factory, think of 480/277V as feeding the infrastructure (e.g., HVAC, lighting, elevators, plant air) and produc- tion equipment and 208/120V as feeding controls and offices. For a commercial building, think of 480/277V as feeding the infrastructure, and 208/120V as feeding everything else.
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Depending on what 480v system is feeding the facility, you may or may not need a transformer to derive 277V
 
I recently inspected a facility with a 6000 amp 480/277 service. Due to the high available fault current, the engineer used a 480 to 480/277 transformer for the lighting panel to reduce the fault current available at his lighting panel.
Also, a xformer states, they facility might have 480v (only) service.
 
Every transformation has losses .... maybe 1.5%. If you can use the 480V to run motors and other items that can take in 480V directly, then that is less load that has to go through the "lossy" transformation process
 
ron said:
Every transformation has losses .... maybe 1.5%. If you can use the 480V to run motors and other items that can take in 480V directly, then that is less load that has to go through the "lossy" transformation process
Click to expand...

would it actually be less load? Or provide for a more efficient overall system?
 
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Distributing 480V will be less expensive than distributing 480Y/277V because you do not need a neutral for the 480V. In an industrial setting where a lot of the load is 3-phase than you don't need the neutral anyway. Where 277V may be needed in limited quantities, mostly for lighting I would think, than you can derive it buy using a smaller 480-480Y/277V transformer.

It's a balance between practical and economical.
 
mstrlucky74 said:
Below is from a research paper I was reading. Question---if your distrusting 480v why do you need a transformer for a 277v piece of equipment. Thanks​
Click to expand...
To generate the neutral from a 480V delta distribution.​
 
mstrlucky74 said:
Below is from a research paper I was reading. Question---if your distrusting 480v why do you need a transformer for a 277v piece of equipment. Thanks



Understand that it is much more efficient to distribute 480V than 120V. The later you derive 120V in the dis- tribution, the higher your efficiency will be. (Distribute at greater than 480V if you can specify a higher voltage service). Two other tips are:​
Use small 480-480/277V transformers to derive 277V as needed. Typical uses for 277V are lighting and HVAC reheat boxes (both available in 480V). Before specifying 480V, ensure the style you need is available in that voltage and you?ve addressed maintainability issues.
Use small (e.g., 15KVA) 480-120/208V transformers to derive 120V near the load, to shorten 120V runs. For a factory, think of 480/277V as feeding the infrastructure (e.g., HVAC, lighting, elevators, plant air) and produc- tion equipment and 208/120V as feeding controls and offices. For a commercial building, think of 480/277V as feeding the infrastructure, and 208/120V as feeding everything else.
Click to expand...
Some good replies of situations where you may not have 277 available, your OP did not say whether or not this was 480/277 supplied to begin with, and if so whether or not the neutral is present at the location where you need one. Reduced available fault current which was also mentined is another good reason even if the neutral is available.
 
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