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Join Date: Mar 2008
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# Neutral Current Transformers (NCT)

09/08/2017 2:20 AM

how is NCT sizing (CT ratio) done for transformers

1. CT ratio = rated current /2

2. minimum 1/3 of rated current

Pathfinder Tags: transformers
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#1

### Re: Neutral Current Transformers (NCT)

09/08/2017 8:27 AM

Why would you choose the CT ratio for any less than the expected rated current of the conductor? Even if it is the neutral, the best accuracy of the CT is within its rated current.

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#2

### Re: Neutral Current Transformers (NCT)

09/08/2017 9:54 AM

This is not resolved by Ohm's law. Better get a circuit protection guide.

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### Re: Neutral Current Transformers (NCT)

09/08/2017 4:52 PM

After looking back nine years, it seems that you live in an information vacuum:

transformer 05/21/2008

transformers 06/29/2008

Transformer Impedance 04/29/2011

You should definitely learn the rudimentary principals of transformer theory!

Here are some suggested reading materials for you:

Principles of Transformers - Access Engineering Library

Transformer:Elementary Theory of an Ideal Transformer | electric ...

Elementary Theory of Ideal Transformer | My Homework Help

Ideal Transformer | Electrical4u

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