CT Accuracy: 5P10, 10B50 and 0.5M5 3

[Sargardani]

Can any one please explain the difference between the following CT accuracy classes?

5P10, 10B50 and 0.5M5

Sarg

 

[Deansharafi]

P is designation for protection. 5P10 means that the CT will have max of 5% inaccuracy when the current of 10 times reated current of CT is experienced.
M is designation for metering. 0.5M means that the CT max inaccuracy is 0.5%
Never seen or heared of 10B50.

 

[tinfoil]

The ...B50 part is a meausre of the maximum burden the CT can carry and still maintain accuracy.


ANSI C57.13 is the relevant guide for instrument transformers.

There's a decent exerpt at the end of this document:

http://www.geindustrial.com/products/buyersguide/GEP-9186-1.pdf

 

[cuky2000]

Dear Sargardani,

The CT accuracy class for 5P10 transformers per IEC Std 60185 is as follow: 5 = max. permissible total error, P= stand for protection and 10= Accuracy limit factor (ALF).

I am not familiar with the other two accuracy nomenclatures (10B50 and 0.5M5). However, the last one has appears to have some similarity with the nomenclature used in the Australian standard for CT’s.

If you should provide additional details such as project location, origin of CT, application, electrical parameter, manufacturer name or any relevant data, perhaps someone could help you.

In addition to the American instrument transformer standard, ANSI C.57.13, enclose are a few popular standards used for CT:

^{International/European: IEC 60044-1,
British: BS 3938 & BS 7626,
German: DIN VDE 0414-1,
Australian: AS 1675
Indian: IS 2705.
Japanese Standard}