Best Conductivity? Regular steel, vs stainless steel, vs zinc coated steel?

@Mannyrock posted:

Hey Guys,

I am going to use steel flat washers on the top and bottom of the pole connections on my Lionel 022 Switches, to create better contact with those skinny switch control wires.  These flat washers come in the three versions listed above.

Any idea which version would have the best electrical conductivity?

Thx,

Mannyrock

I would use copper washes, as copper has better "conductivity" than any of the three you listed.

Agree with copper though brass is about as good and easier to find.

Pete

Both steel and stainless steel are alloys, with hundreds of different material compositions. No way to answer the question without more data. Generally, stainless has a reputation of being a poor conductor. Steel is not much better. The zinc is probably so thin that it has little impact on conductivity.   Copper is the standard for electrical conductivity. Other materials are rated as a percent of copper.  A topical brass will have conductivity of about 30% of copper. I would guess that a typical stainless might have conductivity of about 10% of copper.  

Thanks for these excellent answers.

I going to buy copper washers, and put a thin coat of No-Ox on them when I install them.

Mannyrock

Err,   OK, why can't I find #4 copper flat washers for sale anywhere online?    I see "4mm" copper washers, but I am guessing that that is not the same.

When I search, for instance, for #6 washers, things come up .    But a search for #4 washers, of any metal make, doesn't find me anything.

Thanks for any advice.

Mannyrock

McMaster Carr has them but the fact of the matter is the conduction path is so short it doesn't matter what metal you use. You would need a special instrument to measure that resistance. Any common ohmmeter will read zero ohms.

Pete

You’re just firing a switch with low voltage power inside your house,……if you planned on sending your switches into orbit to chase the Hubble Telescope, then I might could see where conductivity would be worrisome,……you’re way overthinking this …..if you just wrapped the wire around the stud without a nut or washer, they’d still fire just fine …..

Pat

Also brass develops an oxide over time that is non conductive.  My company was developing electronic air brakes back in the 90's and I got a call from ones of my field guys.  The 7000' UP stack train we were testing on was showing intermittent signal problems front to rear.  Having a flashback from my HO brass track days I suggested they unplug and replug the electrical connectors at every car a few times.  The problem went away, and we replaced all the brass contacts with nickel silver just like I did on my HO layout when I was a kid.  Problem solved.  And I got to gloat that my model railroad experience had been useful on a real railroad!

Well, I should have mentioned, that these switches are at the end of a long wire run of 8 feet, and those puny 22AWG switch wires are giving me problems.   The switches often act sluggishly, but not always.  I tested the switches themselves at their poles, by momentarily connecting the center pole to each outside pole, and they always operate very crisply and sharply.   

So, I believe the problem is the long run of thin wire.  I will probably have to replace those long wires with 18AWG to get them to work better, but before I go to that trouble, I thought I would just see if I can get a better connection of the thin wires to the poles, using copper and No-Ox.  Perhaps it won't work, but it is a cheap experiment and maybe it will work.

Thank,

Mannyrock

Adding a washer won’t decrease the resistance of the path of the wire to the switch terminal, it can only increase by adding another component in the current path. It will help in preventing a stranded wire from spreading out under the pressure of the twisting nut. The majority of the current goes from the wire to the stud including its base, not up through the nut. You are splitting hairs.

Just use larger gauge wire. If you want to increase contact area better to use a round wire lug with the wire soldered to it.

Pete

@harmonyards posted:

You’re just firing a switch with low voltage power inside your house,……if you planned on sending your switches into orbit to chase the Hubble Telescope, then I might could see where conductivity would be worrisome,……you’re way overthinking this …..if you just wrapped the wire around the stud without a nut or washer, they’d still fire just fine …..

So, I have to ask.

I see pictures of huge layouts on this Board and online.   There must be some really long switch wire runs in these layouts, as much as 12 to 16 feet.  And, if they operate switches in pairs with a single controller, then there may even be a second long set of wires running from the master switch motor to the slave switch motor.

So, what are these folks doing about those lousy 22AWG wires that come with the controller switch?    Are they routinely replacing the control wires with something heavier? 

Thanks for any info.

Mannyrock

@Mannyrock posted:

So, I have to ask.

I see pictures of huge layouts on this Board and online.   There must be some really long switch wire runs in these layouts, as much as 12 to 16 feet.  And, if they operate switches in pairs with a single controller, then there may even be a second long set of wires running from the master switch motor to the slave switch motor.

So, what are these folks doing about those lousy 22AWG wires that come with the controller switch?    Are they routinely replacing the control wires with something heavier?

Thanks for any info.

Mannyrock

Well, the wires that come with the switch controller are only a few feet long, so you can just run them to a terminal block and run heavier wire.  You can also cut them shorter if you put the terminal block near the switch controller.

If you assume each switch draws 2 amps and you have two in parallel, a 15 foot run (dual conductor) would require #16 wire to minimize the voltage drop to one volt.  Obviously, if you only have one switch on the controller, you have half the voltage drop.

If you decided to run the #22 wire, you'd have to consider a 3V maximum voltage drop.

As long as your connections are tight, I doubt the type of washer is going to change anything.  You can also add something like DeoxIT D5 to the terminal to improve the conductivity if that makes you feel any better.

I used O22 switches for years, and I used #22 wire that went at least 15 feet, I never had any problem with power drop causing an issue.

I think Pat is right, you may be overthinking this.

Gunrunner,

Thanks very much for that excellent information.

All I can say is, that I don't believe I am overthinking this, because the dang pair of switches are not getting enough juice from the controller to flip them smartly and reliably.   (Is it possible that the controller itself is no good?)

Worse yet, this pair of switches is central to the layout, and lots of "rail traffic" has to pass over them.

Funny that you mention 16 AWG wire.  I was so frustrated last Sunday when I was fooling with this, that I ordered a big spool of 16 gauge wire, swearing that I was going to solve this problem once and for all!

I am going to take your advice, and install a terminal block very close to the controller and run the heavy wires from there.

As Popeye use to say, "I've had all I can stands, cause I can't stands no more!"

Mannyrock

Did you try connecting the controller close to the switch and see if it works reliably there?  Also, why not simply boost the voltage a couple of volts to account for any wire drop?

Instead of copper washers why not use solderless terminals?  I would definitely get some heavier wire.

Thanks for the advice Gunrunner, but I think I'll do the Russian solution, which is a massive overbuild using large amounts of metal and 1920s technology.

Mannyrock

@Mannyrock posted:

Thanks for the advice Gunrunner, but I think I'll do the Russian solution, which is a massive overbuild using large amounts of metal and 1920s technology.

Don't go to war that way, look at what's happening to the Russian tanks in Ukraine.