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John Robertson <spam@flippers.com>: Jan 06 11:31AM -0800 > On Friday, January 6, 2017 at 9:52:54 AM UTC-5, avag...@gmail.com wrote:   >>> SNIPPAGE<<   > a) Wire conductivity, irrespective of material, is a function of surface area and gauge amongst other factors. So, if 14-gauge wire is then divided into strands, the final product with the most strands will have the most surface area, and so by some factor greater conductivity.   At 60 Hz in copper, the skin depth is about 8.5 mm, slightly thicker than gauge 0. You are talking about skin effect which is only starts to show above a few kilohertz, otherwise the raw diameter of the wire is what carries the current. Multi-strand wire (such as power cords, or speaker wire) is convenient as it flexes, but it carries no more current than an equivalent solid core wire at frequencies under around 10kHz. For transmission towers where the outer diameter of the wire is much larger that 8.5mm dia, then uses multi-stranded wire to get around it.     > b) Using material conductivity hierarchy, the most conductive material wants to be on the surface. Aluminum is a much poorer conductor than copper. All other things being equal, aluminum coated copper will be a poorer conductor than copper-coated aluminum (or steel: c.f. CopperWeld).   If you are comparing wire coated with aluminum vs a copper wire of the same diameter as the coated, then yes, the plain copper would conduct more current.     > c) Corrosion is a factor, but not much of one. Alumina (AKA Aluminum Oxide) is an excellent insulator, as well as being quite inert. As aluminum wire acquires an oxide coating very nearly immediately upon exposure to air, that will reduce conductivity on the immediate surface of the wire. But as that coating is only a very few nanometers thick, the effect is near-zero overall. Copper oxides and sulfates as well as various other 'salts' are variously conductive, but also can be rectifiers, so there will be some effect on overall conductivity in the presence of these materials. BUT, copper is not a very active metal, so oxidation under normal atmospheric and environmental conditions is low and slow. Similar to Aluminum, but for different reasons.   Of course corrosion will show up as a problem at connection points, but rarely does it matter for regular wire. Battery leakage though was a big problem with electronics designed in the 70s to 90s - but that mostly affect circuit boards and the connectors to them. Battery and salt are factors for wire corrosion in vehicles.   > d) Electrolysis is always a factor when dissimilar metals are forced into a conductive connection in the presence of oxygen or other oxidizers. For an interesting experiment, take an ordinary 16D nail, wrap a bit of copper wire around it, and place it in a glass of ordinary tap water. In an adjacent glass place a similar nail, no copper. Then a bit of copper, no nail. Do the same with an aluminum wire bonded to a copper wire (mere wrapping may not insure sufficient connectivity for electrolysis to take place. Copper clad materials generally do not suffer as there is very limited surface area exposed.   Interesting. Thanks. The results probably depend on the hardness of your water...     > Enjoy!   > Peter Wieck > Melrose Park, PA   Indeed, have a good day!   John :-#)#   -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

"pfjw@aol.com" <pfjw@aol.com>: Jan 06 12:03PM -0800 On Friday, January 6, 2017 at 2:32:01 PM UTC-5, John Robertson wrote: > equivalent solid core wire at frequencies under around 10kHz. For > transmission towers where the outer diameter of the wire is much larger > that 8.5mm dia, then uses multi-stranded wire to get around it.   In the words of the prophet: Yabbut!! (Yes, but!)   Most discussions around wire material and types wind up, at least at some point, around speaker wire discussions. Hence the reference to surface area being an advantage. Speaker wires commonly carry in the multi-kHz frequencies.   For normal household use the difference will be negligible, and in some specific conditions actually favor solid conductors. And to be a tiny bit snarky: "There is a formula for that".   My specific choice for speaker wire is #12 19-strand THHN wire chucked and twisted in a drill for easier handling. Quite manageable and extremely tough.   Peter Wieck Melrose Park, PA

dplatt@coop.radagast.org (Dave Platt): Jan 06 12:52PM -0800 In article <65b7626d-4679-4d55-8177-5e20db49635f@googlegroups.com>,   >In the words of the prophet: Yabbut!! (Yes, but!)   >Most discussions around wire material and types wind up, at least at some point, around speaker wire discussions. Hence the reference to surface area being an >advantage. Speaker wires commonly carry in the multi-kHz frequencies.   Yup. But, my recollection is that the "surfaces" of the individual wire strands are almost irrelevant for speaker wire. The strands are packed together, and are in frequent-enough electrical contact with one another that they behave electrically in a way very close to that of a solid wire. You don't get an additional "skin effect" conductivity win from the individual "skins" of the individual strands.   So, high-audio-frequency performance tends to be influenced more by the bulk inductance of the cable than by the solid/stranded issue. Using four conductors in a "four-cross" confirmation can help with this.   >My specific choice for speaker wire is #12 19-strand THHN wire chucked and twisted in a drill for easier handling. Quite manageable and extremely tough.   Sounds like a good economical choice.

avagadro7@gmail.com: Jan 06 12:55PM -0800 they just flip out   electrical current, here 12v+ DC in an auto primary wire does not seek the least obstructive path that is at the interface of copper n aluminum cladding ?

Jon Elson <jmelson@wustl.edu>: Jan 06 03:18PM -0600 >>>SNIPPAGE<<   > a) Wire conductivity, irrespective of material, is a function of surface > area Shouldn't that be CROSS-SECTIONAL area? > and gauge amongst other factors. So, if 14-gauge wire is then divided > into strands, the final product with the most strands will have the most > surface area, and so by some factor greater conductivity. Yes, but actually, I think the conductivity is better with FEWER strands of thicker wire. Many strands of tiny wire ends up being a lot of air and not so much copper.   As for the original poster, that silvery coating on typical stranded wire is tin or solder, NOT aluminum. It is there mostly to make the wire solderable, but also acts as a corrosion inhibitor.   The only aluminum wire is used as power lead-ins to houses, as it is much cheaper than copper. They did use aluminum wire INSIDE houses in the US around 1966-1968, and it burned a lot of houses down, due to the cold flow of aluminum weakening the contact force.   Jon

Ralph Mowery <rmowery28146@earthlink.net>: Jan 06 05:02PM -0500 In article <N5ydneYpyOkclO3FnZ2dnUU7-dvNnZ2d@giganews.com>, jmelson@wustl.edu says... > around 1966-1968, and it burned a lot of houses down, due to the cold flow > of aluminum weakening the contact force.   > Jon   I got some wire of 16 and 12 guage to use for 12 volt power wiring. It may have been called speaker wire. A red and black pair. The wire turned out to be aluminuim with a coating of copper.   I have seen some coax where the center conductor is aluminum with a coating of copper, but this is for use at radio frequencies where the skin effect is very much in effect.

Phil Allison <pallison49@gmail.com>: Jan 06 06:01PM -0800 > using http://www.powerstream.com/Wire_Size.htm   > is there a functional difference, other factors ie metal purity equal,   > between 8-12-14> gauge wire having 10 strands and 25 strands ?   ** Yes, stranded wire is far more flexible.     > does covering each copper strand with aluminum coating increase > conductivity ?     ** Aluminium wire is often coated in copper, not the other way around.   It improves conductivity and most importantly makes it possible to solder the ends.   Sometimes it is passed off as being pure copper to the unwary.       .... Phil

avagadro7@gmail.com: Jan 06 06:18PM -0800 On Friday, January 6, 2017 at 9:01:07 PM UTC-5, Phil Allison wrote:   > Sometimes it is passed off as being pure copper to the unwary.   > .... Phil     accessed the specs via 4 lines of ID codes.....copper inside, aluminum coating outside, 25 strands Ga 12 has a mil spec rating   difficult scraping the silver off with a new utility blade

Phil Allison <pallison49@gmail.com>: Jan 06 06:59PM -0800 > accessed the specs via 4 lines of ID codes.....copper inside, > aluminum coating outside, 25 strands Ga 12 has a mil spec rating   ** Kindly post in plain English - not pure gibberish like the above.   I have never heard of Aluminium clad Copper wire and neither has Google.   Where have you ?     .... Phil

Phil Allison <pallison49@gmail.com>: Jan 06 08:31PM -0800 Ralph Mowery wrote:     > I have seen some coax where the center conductor is aluminum with a > coating of copper, but this is for use at radio frequencies where the > skin effect is very much in effect.   ** Copper clad aluminium wire ( aka CCA ) is commonly used for loudspeaker voice coils - enamel coated of course.   The advantage is lower weight compared to pure copper, leading to more dBs per watt.     .... Phil

jurb6006@gmail.com: Jan 06 11:46PM -0800 >"The advantage is lower weight compared to pure copper, leading to more dBs per watt. "   Depends on the application, the advantage might be negligible. The mass will certainly matter more at higher frequencies, so these big massive cones on speakers in sound reinforcement bass bins might not benefit quite so much as say a woofer in a decent quality two way home speaker.   I also have heard of copper clad aluminum wire for other purposes and usually it is to save money. One instance it is wires strung from telephone poles. Alot of that is copper clad steel for the tensile strength, again because of cost but not just the cost of the copper, they can put up longer spans and have to set less poles.   I can't think of much reason for aluminum clad copper.

avagadro7@gmail.com: Jan 07 04:44AM -0800 A quantity of aluminum tineed or clad (?) Material online but not specifically answering my question beyond the general rules of surface conduction.   An absence, in a brief surface read, led to a conclusion there's not a serious difference tween copper m aluminum clad copper. An original patent sez there is a layer of silver molecules between...in 1956, WE.   And the advantage is the AL clad wire is less reactive to insulation at higher temps.   Last question: when soldered is the joint as conductive as copper solder copper ?   Silver melts streams off solder joins copper copper with a low % aluminum.   I used the new aluminum clad wire giving a less conductive result but there are other available reasons for the result so a redo. Maybe a direct conparison.

Jon Elson <jmelson@wustl.edu>: Jan 06 02:05PM -0600 >> Jon   > A couple.   > a) Some sort of restriction in the flow through the detergent cup. Yup, I thought of that. So, I rigged a length of tube to the detergent valve. Same result, about a trickle. Yes, there must be a restriction in the manifold to slow down the flow to these three dispensers, or they'd overflow all over the inside of the machine. But, I have THREE valve units aquired during diagnosing of various faults oveer the years, they all do the same.   > detergent cup *and* the drum when filling. If yours is different, make > sure that the flow through the detergent cup from the pump is > unrestricted. The detergent cup is filled through the water supply, not by a pump.   > b) The valve that switches from cup to drum may be sticking > such that it does not permit full flow when in the detergent position.   Well, the direct fill valve is all by itself, upstream of the resriction. It is not part of the other valves. > assemblies, I would suggest you tear one down via destructive demolition > and see how it 'goes'. That may give you a clue as to what is going on > now. Well, hate to destroy a "good" valve, they are pretty expensive. I am pretty sure that the electronics/relays are turning OFF the power to the direct fill valve, and that it is NOT a problem in the valve/solenoid. The bypass wire I put in seems to be working, so that any time EITHER relay is closed, both valves open. So, it seems to have fixed the main complaint, which was either very long wash cycles or the machine stopping with an error code. I'm fairly tempted to just stop here, as I can't see a downside to letting it run indefinitely like this. My wife does not even USE the detergent cup, or any of the other dispensers, anyway!   Thanks,   Jon

Jon Elson <jmelson@wustl.edu>: Jan 06 02:19PM -0600 > Whoops! One more thing. Set the level control higher on the initial fill, > if that is in any way adjustable. Then there would be less time required > for the remaining fill. If this is a timing fault, that might cure it. Well, you do have a control on the amount of water used, by selecting different cycles - it has about 10, ranging from small load to sheets/towels. The sheets/towels cycle would get 3 or more LF shutdowns and take some 30 - 45 minutes to fill the basket enough for the washing action to start. It now fills for that cycle in maybe 6 minutes with no shutdowns.     But, I have no way to set the times for different parts of the filling. That's all in the microprocessor. It probably does make that decision based on either the water level sensor or by deciding when the clutch disengages. It has one motor that is directly connected to the agitator in the bottom of the basket. The basket has a spling clutch to the motor shaft, and an air ring on the bottom. When the tub fills to a certain depth, the basket rises and disconnects from the motor, allowing it to agitate. Before the fill/lift/disconnect, it uses the motor to "weigh" the load, via sensing the rotational inertia.   Jon

jurb6006@gmail.com: Jan 06 11:50PM -0800 Hate to say it, but the best solution is to go to a thrift store and get about a 30 old model.   I shall not buy new appliances.   Want more reason for that ? Look up a site called "Made By Monkeys". After reading that for a while you won't want anything new.

Jon Elson <jmelson@wustl.edu>: Jan 06 04:14PM -0600 > absorbs moisture. Your vacuum pump idea is a good one. I wonder how > long it would take to dehydrate a hot tub cover. Maybe wait 'till the > middle of winter and freeze dry it. Yeah, right. Ice diffuses slower than liquid water, which diffuses slower than water vapor. So, freeze drying only works if you can then slam it against a wall and break all the ice off, which I think is NOT what you want.   Jon

Jon Elson <jmelson@wustl.edu>: Jan 06 03:24PM -0600 Jeroni Paul wrote:   > paper. The text "HP Explorer" and "Information" has already passed over > the paper and most toner remains in the drum, so the text in the paper is > almost indistinguishable.   OK, as some of the image seems to be from several revolutions of the drum past, that does seem to indicate the wiper blade is not working. There should only be ONE part of the image on the drum. The corona wire that charges the drum can only work properly on a CLEAN drum! So, once the drum has a whole bunch of toner all over it, it will not charge properly, and thus the opposite charge on the paper will not work as effectively to pull the toner OFF the drum onto the paper.   I have had VERY similar results, and replacing the wiper blade made the printer work like brand new.   Jon

"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Jan 06 08:01PM "amdx" <nojunk@knology.net> wrote in message news:o4mof1$oq3$1@dont-email.me... > the math, I'm not one of them. > If it were me, I'd change both diode and transistor to silicon and see > how it works. I think it will.   It looks like the diode generates a reference voltage - that needs to be kept in step with the Vbe of the new transistor.   The silicon transistor still needs more Vbe to get it conducting, so I suspect the sense resistors will also need some adjustment.

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