niteflyer46
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- Celina, TX, USA
Is it necessary to correct inductive reactance for temperate changes?
temperature correction for ac-inductive reactance
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luckylerado
Senior Member
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- Lake of the Ozarks
There are many things that affect inductance and inductive reactance. Temperature is not one of them unless you consider that temp could very slightly affect the size and shape of a coil and or core.
There is not a correction that I am aware of and NEC would certainly not address this.
I have seen some manufacturers provide temp correction for AC / DC resistance of conductors which would be a critical part of an impedance calculation but again I do not believe NEC has addressed this.
There is not a correction that I am aware of and NEC would certainly not address this.
I have seen some manufacturers provide temp correction for AC / DC resistance of conductors which would be a critical part of an impedance calculation but again I do not believe NEC has addressed this.
winnie
Senior Member
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- Springfield, MA, USA
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- Electric motor research
I apologize for not doing a better job of clarifying context. As I mentioned in your other thread, in the general case, temperature can change inductive reactance. By 'general case' I mean situations including intentional inductors, intentional inductor cores, etc. If you are designing a system that depends upon a component having the proper inductance, you cannot ignore temperature.
For purposes of the NEC, and calculating things such as the inductive reactance of feeders and the like, I strongly suspect that any temperature effects are negligible. The inductance of a feeder is an incidental and minor component of the entire system design, with things like the inductive reactance of the supply (transformer/generator) and load being much greater.
Trying to calculate a temperature correction for such a minor component of the entire circuit is likely folly. Having not actually done the calculation, I would bet a beer that the normal and expected manufacturing tolerance for conductor cross section (which changes resistance) will have a larger effect than the reactive impedance change resulting from temperature changes over normal operating temperatures.
-Jon
For purposes of the NEC, and calculating things such as the inductive reactance of feeders and the like, I strongly suspect that any temperature effects are negligible. The inductance of a feeder is an incidental and minor component of the entire system design, with things like the inductive reactance of the supply (transformer/generator) and load being much greater.
Trying to calculate a temperature correction for such a minor component of the entire circuit is likely folly. Having not actually done the calculation, I would bet a beer that the normal and expected manufacturing tolerance for conductor cross section (which changes resistance) will have a larger effect than the reactive impedance change resulting from temperature changes over normal operating temperatures.
-Jon
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