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electricalexpert65
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CT Accuracy

06/03/2019 5:30 AM

Class 0.5S CT connected to Class 1.5 Analogue Meter and Class 0.5S Digital Meter. What will be the overall accuracy? Burden is adequate.
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PWSlack
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#1

Re: CT Accuracy

06/03/2019 5:52 AM

It will be that stated in the manufacturer's literature for those particular items, the detail of which has been withheld from the forum.

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electricalexpert65
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#2
In reply to #1

Re: CT Accuracy

06/03/2019 6:43 AM

At least in this part of the globe, I have not come across any such detail with any such meter/CT manufacturer.

Please provide some links of such manufacturers.
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PWSlack
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#4
In reply to #2

Re: CT Accuracy

06/03/2019 7:19 AM

Links can be obtained using any internet search engine, so the invitation is declined.

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tonyhemet
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#7
In reply to #4

Re: CT Accuracy

06/04/2019 1:24 AM

I wanted to give you a good answer, but, because, you are already in the red, with 5 off topics, the only answer that the system will allow, is for me to give you, 1 less off topic answer.

If I give you 1 less off topic answer & 4 others give you a less off topic each, then you will be at the starting point for off topic and good answers.
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TonyS
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#3

Re: CT Accuracy

06/03/2019 6:49 AM

http://www.dk-moriarty.ltd.uk/

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NotUrOrdinaryJoe
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#5

Re: CT Accuracy

06/03/2019 12:04 PM

I think you are looking for the general equation which is the square root of the sum of the squares of each individual accuracy.

Of course since we don't know the accuracies of the individual devices, we can't calculate that for you.

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electricalexpert65
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#6
In reply to #5

Re: CT Accuracy

06/04/2019 1:18 AM

I have indicated that there are only two devices connected to the CT. One analogue MW Meter of Class 1.5 Accuracy and one Digital Multifunction Meter of Class 0.5S Accuracy. The CT accuracy is Class 0.5S. The burden is taken care of. Please give your solution now.
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TonyS
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#8
In reply to #6

Re: CT Accuracy

06/04/2019 1:40 AM

Please give your solution now.

You’re very demanding seeing as you're asking for our help.

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IWANUSIW
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#11
In reply to #6

Re: CT Accuracy

06/05/2019 2:46 PM

The manner in which you are providing the information and asking for answers indicates that you are ignorant of the subject matter at hand.

To provide you with a reasonable answer please supply the following information:

1. What is the "burden rating" of the 0.5S CT?

2. What is the burden of the 1.5 Class analog meter?

3. What is the burden of the 0.5 Class digital meter?

4. What is the burden of your wiring?

As the accuracy of the CT, and the meters vary with load current, at what particular load current would you like the accuracy to be provided.

As this is a "gentle men's" forum, it is most inappropriate to use such terms as "GIVE YOUR SOLUTION NOW".

"Can someone provide me with a solution, PLEASE" would be more appropriate.
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Just an Engineer
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#9
In reply to #5

Re: CT Accuracy

06/04/2019 7:35 AM

Hello, I think that you are close with that equation, but with some modification for parallel or series readings.

From memory, it also relies on all instruments being in the same confidence interval (95% or 99% etc) or else other corrections need to be made.

The OP might need to calculate the error function for each branch if they lead to "independent" readings across the same CT device.

Of course they will need to include the error function of the CT also.

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raghun
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#10

Re: CT Accuracy

06/04/2019 8:47 AM

"Burden is adequate" - IEC says the stated accuracy of the CT is valid in the burden range 25-100%.

Thus, if the connected burden happens to be <25% of CT rated burden, the measurement errors could exceed 0.5%.

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Anonymous Poster #1
#12
In reply to #10

Re: CT Accuracy

06/26/2019 12:18 AM

https://sdvelectrical.blogspot.com/2018/09/accuracy-class-of-current-transformer.html
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211kevinrichard
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#13

Re: CT Accuracy

06/27/2019 8:59 AM

I will try to post some pics later, but I just made a project box using one of these from:
http://www.yagionline.com

The PCB was a wired madcatz 360 pad. And all I had to do was desolder the analog sticks - pull them off, and I left the variable resistors on and glued them in place.
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Users who posted comments:

211kevinrichard (1); Anonymous Poster (1); electricalexpert65 (2); IWANUSIW (1); Just an Engineer (1); NotUrOrdinaryJoe (1); PWSlack (2); raghun (1); tonyhemet (1); TonyS (2)

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