Conductor current

As conductor current one is by a electrical conductor guided electric current referred to, when it is connected with the transport of freely moving electrons and not with a material change. It can flow without the need for a minimum electrical voltage or current.

Electricity from a source to a consumer with at least two conductors

A consumer to which electrical energy is to be supplied by means of a conductor current always requires at least two such conductors, between which there is an electrical voltage . These are seen as the forward and return conductors of a circuit , in which the statement applies to every instantaneous value of the current in the picture opposite . Or one says that in the sum of all conductor currents, current cannot flow to the consumer at any time, expressed by . Here are different and only in sign because of the inverted arrow directions. ${\displaystyle i_{1}=i_{2}}$ ${\displaystyle i_{1}+i_{3}=0}$ ${\displaystyle i_{2}}$ ${\displaystyle i_{3}}$

In some circuit diagrams , the return line is missing, as shown in the lower part of the picture. But the circuit symbols shown for ground indicate that these connections are connected to one another, for example via a housing. Accordingly, there is only one conductor wire for lighting a bicycle if the return line is possible via the supporting structure and the mudguard.

Current from a source to a consumer with three outer conductors L1, L2, L3 and a neutral conductor N.

In electrical power engineering in particular , three or four current conductors for three-phase alternating current (“three-phase current”) are widely used. A distinction is made between external conductor current and neutral conductor current , and in some cases also middle conductor current and protective conductor current . With a circuit like the one in the picture, the three outer conductors are evenly loaded ; then the neutral conductor can be missing. ${\displaystyle i_{1}+i_{2}+i_{3}=0}$

A conductor current must not be arbitrarily large because of the line resistance and the resulting Joule heat , which must be dissipated in order to avoid overheating. This leads to standardized empirical values ​​about the maximum permissible current density in cables or the minimum required conductor cross-section.

Individual evidence

1. ↑ DIN 40108: 2003-06 Electrical power engineering - Power systems - Terms, sizes, symbols