What is D.F and How to Calculate It for Transformer Load?

[JUJU_100]

I have seen an excel sheet in calculator to calculate the size of transformer.
There are option to put the vales of Kw,PF,Qty and Equipment D.F.
I could not understand what is D.F.
What is the equation to calculate the D.F and equation to calculate the total load D.F?

 

[anorlunda]

Do you mean dissipation factor? If so, this article may help.

https://en.m.wikipedia.org/wiki/Dissipation_factor

 

[CalcNerd]

D.F. likely means equipment Demand Factor. If the equipment is a stove or Washing and Drying machines in an apartment complex that furnishes these appliances, they would generally not all run at the same time. The NEC (National Electric Code) provides tables that allow you to reduce the size of the service transformer instead of calculating with all the equipment at 100%.

 

[JUJU_100]

This is the link of the excel sheet- D.F factor of Equipment-

http://electrical-engineering-portal.com/download-center/electrical-software/calculation-of-size-of-transformer-fuse-and-circuit-breaker#comment-12292

 

[Tolklein]

I would have assumed derating factor. This would be a fudge factor thrown in where equipment spec is derated. Usually by around 20% as a rule of thumb.

 

[JUJU_100]

I didn't see fudge factor in the spec.
Can anyone help me to calculate the D.F load?

 

[Tolklein]

Ah, I didn't read the spreadsheet properly the first time, I believe CalcNerd is correct.
https://en.m.wikipedia.org/wiki/Load_factor_(electrical)

 

[JUJU_100]

Please See the below screen shot. Find the highlighted area