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Current Transformer Thermal Factor

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CuriousElectron

Electrical
Joined
Jun 24, 2017
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196
Location
US
Hi Gents,
I had a question - is the thermal factor rating on a current transformer refer to continuous or overload capability of an instrument to carry increase in current? For example, if 1000:5 CT has TF of 2.0 at 40 degree C ambient, does this mean that this device can carry 2000Amps continuously at 40 degree constant ambient temperature?
Thank you for clarifying.
EE
 
Curious: Take a look at both IEEE Std 57.13 and the following link (which explains how the Thermal Rating Factor is applied).


The short form is that for higher thermal factors, the local ambient must be MUCH lower, because the CT winding total temperature (ambient plus rise) is limited to 85 C.

Converting energy to motion for more than half a century
 
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