baltoche

Hi Sorry for the delay (I had'nt been notified you responded). I confirm I wish to measure the AC resistance of a piece of rail. Regading AC vs DC resistance, it is right that it should be the same resistance. However, due to the skin effect, the surface where he current flows is reduced in AC, affecting the resistance. I consider his is not part of the reactance but well the resistance. I do agree with your method consisting in making the frequency vary, but all measurements in AC will include both the DC resistance, the skin effect and the reactance. Therefore, I cannot get rid of the reactance itself and I cannot get the resistance in AC (with the skin effect). When you write "A simple way to effect the measurent is to insert a non inductive high resistance (in comparison to the rail resistance you are measuring) in series with the source to cause it to be a constant current source. Measuring the voltage then give a direct readout of the resistance or impedance.", do you mean that I inject an AC current and I measure the voltage drop accross both the rail and the non-inductive resistance ? Thanks for your support.

Hi, I'm working for the railways. One of the project works at 60Hz but I've only got the electrical resistance in DC while I need the resistance in AC at this frequency. If I measure it by impressing an AC current, then I'll measure the self-inductance with the resistance. Unless there is a measurement method I don't know. I tried to approach the problem with another method, by calculating the skin effect thickness but I don't know about the magentic permeability of my rails (high carbon rate).

Hi, I need to calculate the resistance in AC of a steel conductor that is not round. Is there a way to get it from the DC resistance and the shape of the conductor ? Or is there a way to measure it without the self-inductance ? Thanks.