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Anonymous Poster

DC Current & CT

05/17/2010 5:12 AM

I will be thankful if any one can help me out of this. How DC current is sensed by CT.

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Guru
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#1

Re: DC current & CT

05/17/2010 7:01 AM

CD current can be sensed by a Current Transformer only when it's value changes. Other devices (such as a Hall Effect probe) may be used for "non-invasive" DC current measurement.

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Anonymous Poster
#2

Re: DC current & CT

05/17/2010 7:04 AM

hi Guest,,,

as far as I know that the CTs are based on the phenomena of electric induction according to Faraday's law, this means that the CTs can't be applied to the DC current .

Thanks................

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Power-User

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#3
In reply to #2

Re: DC current & CT

05/17/2010 7:07 AM

hi Guest,,,

as far as I know that the CTs are based on the phenomena of electric induction according to Faraday's law, this means that the CTs can't be applied to the DC current .

Thanks................

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Guru
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#4

Re: DC current & CT

05/17/2010 7:41 AM

i have come across DC current transformers in a large chemical plant. Not having any need for such things myself, i did not pursue the subject, just remember faintly that the DC saturated the core and a known AC signal was superimposed .. so on. Well, the DC CT is well documented in many websites, and it may be worth while for you to study this patent..

DC CT Patent

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Anonymous Poster
#5

Re: DC Current & CT

05/17/2010 11:56 PM

Thanks all for the reply. My question is how DC current is measured by CT in DCDB.

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Guru
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#6
In reply to #5

Re: DC Current & CT

05/18/2010 12:13 AM

There are many suppliers of DC CTs ... you can google for one in your region. Here is one...

amprobe

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Guru
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#9
In reply to #5

Re: DC Current & CT

05/20/2010 4:04 AM

Dear guest, i am sure you are busy with many other things, and haven't had the time to check out replies on this thread. i guess if you are not registered, there is no way CR4 can send you a mail telling you that there is a response to your thread. Well, as and when you do see this thread again ... will you please check the patent i mention ? and having read it, if you still don't understand, maybe some more experts will get involved and explain ? Good for everyone who do not know this subject.

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Guru
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#7

Re: DC Current & CT

05/18/2010 4:20 AM

Transformers work on changing currents, so it isn't immediately obvious how a current transformer could ever give anything sensible when connected to a DC supply.

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Guru
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#8
In reply to #7

Re: DC Current & CT

05/18/2010 5:17 AM

i wouldn't have believed it if i hadn't seen it in operation.

It works on the principle of asssessing the saturation level of the core, by superimposing a known AC wave and then measuring the output. Fully explained here: DC CT Patent 4626777.pdf

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