Author Topic: Electrical Bending of Wire  (Read 2203 times)

0 Members and 1 Guest are viewing this topic.

Edward

  • Newbie
  • *
  • Posts: 9
Electrical Bending of Wire
« on: September 09, 2005, 05:48:49 AM »
Has anyone noticed,or has a reason,why a #3(?) multi stranded copper wire bends, when about 300 amps of D.C. current is shorted through it?Ive worked on cars for years,

and when I get a starter that is shorted out,Ive noticed,when under the hood,

the positive cable,if long enough,will try to bend.It moves.Ive never tried to bend the  wire to see if its turning solid.Is this the magnetic field of the wire reacting to Earths magnetic field?Or is it the electron current trying to straighten the wire?Ive tried to measure,using a micro-gram scale,if the weight of the wire was actually decreasing (opposing the Earths magnetic field).Using a very small wire and battery (balance is very picky,all that I have)it appeared that it actually got lighter.Other tests showed it got heavier,I am talking micro-grams of difference and burning wire.Has anyone else observed this?I know this is anologous to a flashlight bulb,(D.C. not A.C.)but those filaments are attached.
« Last Edit: September 09, 2005, 05:48:49 AM by (unknown) »

pyrocasto

  • Hero Member
  • *****
  • Posts: 600
Re: Electrical Bending of Wire
« Reply #1 on: September 09, 2005, 03:15:25 AM »
I've personally never noticed it but have you ever heard of muscle wire? It is easily stretchable wire, soft. When you put an electric current through it it becomes hard again and retracts to it's original shape. It is used in small robotics and such, instead of using small motors or actuators. Maybe something similar there?

« Last Edit: September 09, 2005, 03:15:25 AM by pyrocasto »

richhagen

  • Hero Member
  • *****
  • Posts: 1597
  • Country: us
Re: Electrical Bending of Wire
« Reply #2 on: September 09, 2005, 04:11:35 AM »
I havn't noticed that effect, even with my electric car that can peg a 300 amp meter for a bit.  The wire is a bit thicker, triple ought, though.  I would speculate that you have two things going on.  First, pulling 300 amps through a #3 wire is going to heat it up pretty quick.  That would likely lead to uneven expansion between the insulation and the wire.  Second, at 300 amps, you likely have a noticable magnetic field, which could have an effect on and by metal objects nearby.  Rich
« Last Edit: September 09, 2005, 04:11:35 AM by richhagen »
A Joule saved is a Joule made!