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atchet
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Join Date: Feb 2009
Posts: 33

How to test the polarity of a CT

02/10/2009 10:01 PM

Please help me. I am a new engineer. My boss ask me in how to test the polarity of a CT? and what will be test equipment will be used
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msamad
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#1

Re: How to test the polarity of a CT

02/10/2009 10:15 PM

All you need a 1.5V dry cell battery, a multimeter and few pieces of wire. Connect the multimeter in CT secondary to measure DC current. Quickly connect and disconnect the battery in the primary. You can now find the primary terminal entering the current (connected to the positive terminal of the battery) and secondary terminal exiting the current (from DC ammeter polarity). It is so simple, quick and interesting.

- MS

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atchet
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#2
In reply to #1

Re: How to test the polarity of a CT

02/10/2009 10:49 PM

thank you so much..may i know what are the other standards test of a CT?
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sb
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#3
In reply to #1

Re: How to test the polarity of a CT

02/11/2009 2:00 AM

Very interesting concept. Using a square pulse.

Own ?

OP: For CT testing please refer to standards IEC 60044 for the CT it is part-1

If you are in the ANSI zone it is ANSI C57 series (i think C57.13)

Check these standards.

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Anonymous Poster
#4
In reply to #3

Re: How to test the polarity of a CT

02/11/2009 2:28 AM

thanks
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sb
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#5
In reply to #4

Re: How to test the polarity of a CT

02/11/2009 8:47 AM

who MS or A ?

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Anonymous Poster
#6
In reply to #1

Re: How to test the polarity of a CT

07/31/2009 9:31 AM

good answer
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Anonymous Poster
#7
In reply to #1

Re: How to test the polarity of a CT

01/12/2010 12:51 PM

make sure that you use anlog meter for this test

Thanks

Arvind
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Anonymous Poster
#8
In reply to #1

Re: How to test the polarity of a CT

08/02/2010 6:04 PM

Hi,

Could you explain little more? Because transformer cannot sense DC current due to its inductive property(If it is CT or power transformer).

XL = 2 *pi * f * L

XL - Inductive Reactance (Which opposes current flow like resistance)

pi - constant (3.14)

F - Frequence (In case of DC this equals zero)

L - Inductance

Therefore XL = 0 which means short circuit

Thanks & Regards

Sikander

Design Engineer - HV control & Protection

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Anonymous Poster
#9
In reply to #1

Re: How to test the polarity of a CT

01/22/2011 11:42 AM

the needle of DC ammeter will move clock wise, the clock wise movement of needle shows correct polarity....
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Anonymous Poster (5); atchet (1); msamad (1); sb (2)

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