current rating factor

[Hameedulla-Ekhlas]

Greeting all,

Any idea regarding to current rating factor or an example.

 

[charlie b]

That is a phrase with which I am not familiar. Perhaps you are not using the exact phrase you intended? How did you come across this phrase?

 

[quogueelectric]

Greeting all,

Any idea regarding to current rating factor or an example.

Current rating of What?? Wire,motors,frogs??

 

[mivey]

I think he means the rating factor for CTs.

Read here (I'm too lazy to type):
http://www.uomschool.org/Meter_Book/Table of Contents/CT's/CT's.htm

 

[Hameedulla-Ekhlas]

I was asked by some one about current factor calculation and he said it is regarding to cable distribution

I told him " do you mean maximium current capacity" or what
he told me it is linear or nonlinear load and calculation.

So, It is new for me and dont know it is calculation. I am searching too and if I find anything I will share it.

 

[mivey]

I was asked by some one about current factor calculation and he said it is regarding to cable distribution

I told him " do you mean maximium current capacity" or what
he told me it is linear or nonlinear load and calculation.

So, It is new for me and dont know it is calculation. I am searching too and if I find anything I will share it.

Maybe he means a conversion factor to get to RMS values since the normal assumption is a sinusoidal?

 

[Hameedulla-Ekhlas]

Maybe he means a conversion factor to get to RMS values since the normal assumption is a sinusoidal?

Oh, mivey here I got one example regarding to cable current factor.

Example: Determine the current rating factor (q) for a 60-Hz cable required to carry a nonlinear load with the following harmonic characteristics: fundamental current = 190A, 5th harmonic current = 50A, 7th harmonic current = 40A, 11th harmonic current = 15A and the 13th harmonic current = 10A.

The skin effect ratios are as follows:

[E.sub.1] = 1.0; [E.sub.5] = 1.09; [E.sub.7] = 1.17; [E.sub.11] = 1.35; [E.sub.13] = 1.44.

As previously mentioned, the skin effect ratio (E), also called the ratio of resistance, equals [X.sub.n] / [X.sub.60]. As an example, the skin effect ratio for E5 is based on the ratio of the 300 Hz resistance to the 60Hz resistance, which is 0.301 / 0.277 = 1.09.

The harmonic current ratios are as follows:

[I.sub.1] = 190/190 = 1.0 [I.sub.5] = 50/190 = 0.263 [I.sub.7] = 40/190 = 0.210 [I.sub.11] = 15/190 = 0.079 [I.sub.13] = 10/190 = 0.053 q = [(1.0).sup.2](1.0) + [(0.263).sup.2](1.09) + [(0.210).sup.2](1.17) + [(0.079).sup.2](1.35) + [(0.053).sup.2](1.44)

q = 1.14

Because the cable must be able to handle both the fundamental and the harmonic loads, based upon the q factor, the cable must be rated for a minimum current of (1.14)(190) = 217A at 60 Hz.

 

[kingpb]

So, where does the term come from?

I checked with some IEC experts and he is not familiar with term either.

 

[Hameedulla-Ekhlas]

So, where does the term come from?

I checked with some IEC experts and he is not familiar with term either.

i think this is for industrial and cable design to detemine the ampere capacity of a cable.

Ok any way, it is good to learn a new thing.