Current in an Electromagnetic Coil

[Drakkith]

What keeps the current in an electromagnetic coil from moving between the touching conductors and instead go through the conductor? Is it the resistance being much higher between two touching sections of the coil? Is there a small amount of current "leaking" between each loop where they touch?

 

[Antiphon]

The wires are insulated with a thin varnish-like coating. Usually good to about a thousand volts.

 

[Drakkith]

Is this typical in almost all applications of coils? Would bare copper wires result in a large loss in current through the coil, since the current is taking a "shortcut" to get through the circuit? Or does this depend on the overall resistance of the coil for a current moving through it?

 

[Antiphon]

The only exception would be a special bobbin that prevented conductors from touching. It is a very serious failure mode of a coil (or motor or generator) called a shorted turn. It can be catastrophic- think of it as a secondary turn that's shorted.

 

[FOIWATER]

I agree with everything said here.

We have to make coil groups coated in a thin varnish, as antiphon stated when rewinding motors in our shop at work.

The coating depends on the motor operating voltages

But yeah, just using bare copper.. would surely result in a short circuit, there wouldn't be any turns and therefore no inductance.

 

[Drakkith]

Excellent! Thanks all!