I suspect that somewhere in this thread the issues have been over complicated, by the introduction of factors which have very little effect in the real world.
The inductance of a single wire coiled in 25cm loop in air with 50 turns is less than 10mH - and if the load is purely resistive the return current in the cable will effectively cancel out that inductance.
A solid iron core would increase that very significantly, but you would not be able to lift the reel!
The effective capacitance between the turns will create a complex model which in association with the inductance becomes a tuned circuit. But not of any consequence at 50Hz.
If you want to get detailed why not introduce eddy currents in the core and skin effects of the wire.
I would stick to the explanation of local heating of the cable and the inability to dissipate the heat in the enclosed space of a coiled up cable drum. You only have to look at the necessary derating of conventional domestic wiring when enclosed (eg conduit) vs clipped to joist to get some ideas.
I may try some back envelope calculations later to see the amount of power dissipated in a typical cable reel.
I am happy to be proved wrong - but back it up with some decent theoretical calaculations or a source document with some credibility.
Last edited by: sherlock47 on Mon 20 May 19 at 08:36
|
