Is it still called volt drop in AC circuit? Where the wire and terminator melt? As the the sparkly looked confused when I said volt drop. He said volt drop is voltage drop in the wire it's self. I said I know as the wire is a resistor. But he still didn't get it that the heat was a product of parasitic impedance. Due to loose termination of the wire. Just want to know the correct term.
I don't understand how you don't understand.
Regardless of DC or AC, there's current flowing. There's resistance in everything (except superconductors) and so there is always an induced voltage drop across any circuit with current flow. Current flowing across a resistive path always generates heat, as I x V = Watts. The V is voltage drop, produced by I x R = Voltage.
Substituting, it's I^2 x R = Watts. ALWAYS.
The heat is just not normally destructive, since power distribution circuits are designed with thick enough copper so the energy loss (heat dissipation) is acceptable for the expected current. Still, it's noticeable, as high power circuits do get warm.
Until something goes wrong; for instance a loose connection that develops a few ohms or more of resistance, at 30 amps. Say 2 ohms, that's 30A squared x 2 = 1800 Watts of heating at your screw terminal. Problem...
Here are some pics of a similar problem. A water sterilizer on a ship, these cabinet feed throughs carried about 100A. But the connection tightness depended on the size stability of the plastic insulators. In addition, it's a DC system and the sterilizer needed to have the polarity swapped regularly. I suspect people were not tightening the nuts well after swapping connections over.
It got warm, the plastic distorted, and so the connection got worse and worse. You can see the result. The last pic is of the replacement I made, where all connections depend only on adjacent nuts on the threaded rod. Also, using non-meltable insulators.
Is it still called volt drop in AC circuit? Where the wire and terminator melt? As the the sparkly looked confused when I said volt drop. He said volt drop is voltage drop in the wire it's self. I said I know as the wire is a resistor. But he still didn't get it that the heat was a product of parasitic impedance. Due to loose termination of the wire. Just want to know the correct term.from one point of view. yes it is a "voltage drop", but the fact it occurs at small region (and length), so dV/dl or dV/dv (volume) is quite high, so is the energy dissipated at that particular small region. imagine you cook a food with the same amount of energy. the lesser the food's volume the higher the temperature will be, ie quickly heated up. high temperature will cause mechanical failure. its not necessary applies to only loosen contact, but also on a contigous wire with different diameters along the length, the smallest diameter will produce the greatest heat. the analogy to mechanical system is a notch in a straight bar under tensile force, that notch will fail first. and also it got nothing to do with AC, AC actually is the friend (lower RMS value), DC is worst at causing this. in your case, the heating is much more caused by DC (or RMS) rather than AC.