Any metallurgist in the house?

woodchip · Post by **woodchip** » Sun Jul 18, 2004 4:45 pm

Today I noticed one of my bikes spotlights was not working . Taking the assembly apart I found one of the wires was broken. As you can see I soldered the solid wire to the U connector so I thought I was doing it right. The broken wire comes of the green lead so I'm wondering if that is the positive side. Do any of you have any conjectures as to why the wire broke? To much amps and the wire became brittle?
Oh and in case you are wondering I removed the red plastic covering for visual clarity. Also the grid lines are 1/4" x 1/4".

Grendel · Post by **Grendel** » Sun Jul 18, 2004 5:02 pm

Copper becomes brittle when bent pretty quick. If you have a spot where the wire moves (even only a little bit) it's better to use multi-wire wire (I know, I know -- can't think of the word right now. I hope you get the picture..)

woodchip · Post by **woodchip** » Sun Jul 18, 2004 5:45 pm

Hmmm...well in this case the wire was not bent so I dunno.

Ferno · Post by **Ferno** » Sun Jul 18, 2004 6:11 pm

hm... looks like that was cut..

Jeff250 · Post by **Jeff250** » Sun Jul 18, 2004 7:54 pm

Sabotage!

BAAL · Post by **BAAL** » Sun Jul 18, 2004 8:23 pm

Green lead? usually green is neutral or ground...

Jagger · Post by **Jagger** » Sun Jul 18, 2004 8:39 pm

Probably an imperfection in the metal was amplified by the expanding/contracting motion of the wire due to heat or metal fatigue.

I dunno.

MD-2389 · Post by **MD-2389** » Sun Jul 18, 2004 9:29 pm

To my knowlege, too much current would only make the wire heat up (melting the insulation in the process) not get brittle. That wire was cut, or snapped off.

woodchip · Post by **woodchip** » Sun Jul 18, 2004 10:15 pm

Maybe when I used the wire strippers I used too small a diameter cutting hole?
At any rate it sure is nice having a digi camera that I can post pics for clarification.

Will Robinson · Post by **Will Robinson** » Mon Jul 19, 2004 6:39 am

Nice macro shot.
Green doesn't necessarily mean ground in automobile wiring nor on the Harley Davidson (not sure about Japanese bikes).
As Grendel said, use stranded wire not solid.

Usually the ground wire goes to the frame pretty close to the load to avoid having to run a second wire when the metal frame is already right there. An exception might be if your light is attached to rubber mounted handlebars which would keep the whole assembly from getting grounded to the frame. In that case they would run a dedicated ground.

KompresZor · Post by **KompresZor** » Mon Jul 19, 2004 8:03 am

Like Grendel and Will said, Vibration + Solid core = teh bad.
Stranded wire should fix you up

MD-2389 · Post by **MD-2389** » Mon Jul 19, 2004 12:19 pm

woodchip wrote:Maybe when I used the wire strippers I used too small a diameter cutting hole?
At any rate it sure is nice having a digi camera that I can post pics for clarification.

That might explain it. Anyways, like Will & Grendel said, stranded wire should fix it. Its also alot easier to solder should it become seperated.

Pun · Post by **Pun** » Tue Jul 20, 2004 8:01 am

I can almost guarantee you that the wire break is a result of improper wire stripping. if you nicked the wire when you stripped it, you created a weak point and vibration finished the job. Any, yep, stranded should fix that up no problem. Never use solid bare copper wire on any kind of vehicle.

Pun · Post by **Pun** » Tue Jul 20, 2004 8:03 am

I can almost guarantee you that the wire break is a result of improper wire stripping. if you nicked the wire when you stripped it, you created a weak point and vibration finished the job. Any, yep, stranded should fix that up no problem. Never use solid bare copper wire on any kind of vehicle.