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CT typical resistance value

CT typical resistance value

CT typical resistance value

(OP)
Hi all,

Can anybody suggest typical values for the secondary resistance of these CTs?

50/1 A 15VA Cl. 1
50/1 A 10VA 5P20

These are fairly old CTs and I can't find the documentation from the manufacturer. Nor can I measure it because the plant cannot be stopped right now. My guess is something like 0,2 ohm, and in any case less than 1 ohm.

Thanks

RE: CT typical resistance value

If you know the number of turns and approximate dimensions of the cut and secondary tails you can calculate the figure using the standard resistivity value of copper.

RE: CT typical resistance value

Typical values for the resistance per turn of a CT are in the order of 0.0025 Ohms/turn. It is very unlikely that you are at 1 Ohm for your CT secondary resistance, and probably also below 0.2 Ohms.

RE: CT typical resistance value

(OP)
Afroeeng:
Thanks, unfortunately I don't have the data to make those calculations.

Mgtrp:
That is more or less what I was thinking. I'll assume 0,2 ohm and probably I'm still on the safe side. Many thanks.

RE: CT typical resistance value

Not to split hairs, but not all CTs are window-type CTs. For a HV or MV CT, you may not have any way of knowing the number of secondary turns.

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