Current in an Electromagnetic Coil

Click For Summary

Discussion Overview

The discussion centers around the behavior of current in an electromagnetic coil, particularly focusing on the factors that prevent current from moving between touching conductors and the implications of using insulated versus bare conductors. The scope includes technical explanations and practical applications related to coils in electrical devices.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the resistance between touching sections of the coil is much higher than through the conductor, which prevents current from moving between them.
  • Others mention that the wires are typically insulated with a varnish-like coating, which is effective at high voltages.
  • There is a question about whether using bare copper wires would lead to significant current loss due to short circuits, depending on the overall resistance of the coil.
  • One participant highlights the serious failure mode known as a shorted turn, which can occur if conductors touch, potentially leading to catastrophic outcomes.
  • Another participant agrees with the previous points and emphasizes the necessity of using insulated coils to avoid short circuits and maintain inductance.

Areas of Agreement / Disagreement

Participants generally agree on the importance of insulation in coils to prevent short circuits, but there are varying views on the extent of current leakage and the implications of using bare conductors.

Contextual Notes

The discussion does not resolve the specifics of current leakage or the exact conditions under which bare conductors would lead to short circuits, leaving these aspects open to further exploration.

Drakkith
Mentor
Messages
23,205
Reaction score
7,687
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?
 
Engineering news on Phys.org
The wires are insulated with a thin varnish-like coating. Usually good to about a thousand volts.
 
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?
 
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.
 
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.
 
Excellent! Thanks all!
 

Similar threads

  • · Replies 6 ·
Replies
6
Views
1K
Replies
4
Views
2K
Replies
10
Views
3K
  • · Replies 37 ·
2
Replies
37
Views
5K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 42 ·
2
Replies
42
Views
6K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 8 ·
Replies
8
Views
5K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
12
Views
3K