On Sat, 16 Feb 2019 01:45:43 +0000 (UTC), David Scheidt
wrote:
John B. Slocomb wrote:
:On Sat, 16 Feb 2019 01:06:22 +0000 (UTC), Ralph Barone
wrote:
:John B. Slocomb wrote:
: On Fri, 15 Feb 2019 06:01:11 -0800 (PST), Sir Ridesalot
: wrote:
:
: On Friday, February 15, 2019 at 2:40:00 AM UTC-5, John B. Slocomb wrote:
: On Thu, 14 Feb 2019 19:11:39 -0800 (PST), Steve Weeks
: wrote:
:
: On Wednesday, February 13, 2019 at 8:12:07 PM UTC-6, Radey Shouman wrote:
:
: Almost all of this is unfounded speculation.
:
: There was no speculation at all; well, except for being skeptical about
: aluminum wire. I haven't serviced a Shimano dynohub, so I'll take
: your word for that. But aluminum has only 61% of the electrical
: conductivity of copper, which would make it a strange choice. It's
: cheaper than copper, but Shimano doesn't strike me as being *that*
: concerned with cost in that regard.
:
: Aluminum wire is quite commonly used in "exterior electrical works" -
: house wiring, etc., for two reasons, (1) it is lighter in weight for a
: given gauge and (2) it is substantially cheaper then copper. It is
: common enough that aluminum -copper and copper -aluminum connectors
: are commonly stocked by commercial electrical suppliers.
: See: https://bit.ly/2SytkSg
:
:
: By guess is that Shimano uses the (1) reason :-)
:
: Also, why are you so defensive? I said at the outset that my overhaul
: was of a different hub, but was presented as an example of a dynohub
: repair.
:
: Dan Burkhart has a video of a Shimano dynohub repair he
: https://www.youtube.com/watch?v=oXptXRqxj9c
: It looks like cup/cone bearings as you indicated. Also, unlike the hub
: I serviced, there was no need to unsolder the output wire!
: Hope this helps.
: --
:
: Cheers,
:
: John B.
:
: Aluminium wiring has a VERY BAD reputation in house wiring due to the
: number of fires it has caused. I would NEVER buy a house that had aluminium wiring in it.
:
: Do a search with: aluminium wiring and fires" to see just how dangerous that crap is.
:
: Cheers
:
: You are being a little ridiculous, aren't you. All commercial wiring
: used in the U.S. is rated for it's voltage and amperage carrying
: capacity. Do you actually believe that the aluminum wire makers have
: somehow coherence the rating authorities into over rating aluminum
: wire?
:
: Or perhaps the answer is that a large number of ignorant people
: overload their home electrical circuits and then blame the resulting
: fire on the wires?
: --
:
: Cheers,
:
: John B.
:
:
:Or that early aluminum home wiring systems didn't properly take into
:account the oxidation that always forms on aluminum, and its greater
:thermal expansion, resulting in dangerous high impedance connections.
:
:The fact that aluminum is used from the generating plant right up to your
:doorstep indicates that aluminum can be used safely for high voltage, high
:current circuits. However, either because the home aluminum wiring systems
:weren't properly designed, or because installers didn't install them
:properly, they caused a disproportionate number of house fires, which
:essentially resulting in aluminum house wiring disappearing from the
:market.
:Ask any electrical inspector how many times he has found a coin
:inserted in the old screw type fuse blocks, or oversize fuse wire in
:the even older type of fuses. I have even seen a piece of bent wire
:inserted in a fuse box that was intended to prevent a conventional
:"breaker" from tripping.
What the **** has that got to with aluminum wire? The aluminum wire that
was used for branch circuits in houses in the late sixities and early 70s
is crap. The alloy used was unsuitable -- it has very much movement with
temperature, that movement doesn't match the expansion and contraction
of the devices it's terminated on, and it's very prone to oxidation. In
addition, the devices used allowed the wire to creep, creating loose
connections, which leads to heat, which leads to fire. The stuff is
unsafe, as installed. Poor modifications to it make it worse. Lots of
those have been done by supposedly qualified electricians.
Strange :-) I worked on electrical systems, both interior and exterior
in the 1970's and never found a great deal of difference in the wire
used, in fact sometimes it came off the same roll. I'm thinking of
something like #4 stranded aluminum that we used for both entrances as
well as high current interior wiring. And, by the way, pure aluminum
doesn't corrode to any great extent, or at least there is some stuff
called Alclad that is made from a high strength aluminum alloy sheet
metal clad with a pure aluminum coating. Very commonly used in
aircraft structures see:
https://en.wikipedia.org/wiki/Alclad
There is also an aluminum clad steel sheeting that I've seen used for
roofing and even an aluminum coated steel wire, again used to reduce
corrosion.
\
The aluminum wire that's used for transmission lines is different, and
works quite well for that. So does the aluminum wire that's nearly
universally used for service feeders in the US. So does the modern
aluminum wire that's sometimes used for branch circuits; it's a
different alloy, that has expansion much better matched to the devices
it's terminated in, and the dangers of oxidation and the requirement
to use an anti-corrosive paste on splices and terminations makes it
perform as well as copper.
Also see:
https://www.amesweb.info/Materials/T..._Aluminum.aspx
there seems to be a very small difference between any of the alloys.
--
Cheers,
John B.