Frank, I think that one thing you and I can both agree on regarding this issue is that the COM terminal must be used to power the frog, while the other two terminals (the travelers) must be used to hold the bus wires.
A 3-way household electrical switch is a form of SPDT, so for the author to make it work as intended, when the switch is thrown, power is connected from the bus wires to the wire connected to the COM terminal.
Rich
Alton Junction
Rich,
I wasn't annoyed,, I was just getting too technical. My fault.
Cheers,
Frank
Frank, what I said was that "a neutral wire would never be connected to a switch", and that is absolutely true. Ask any electrician.
Just because a wire is a white colored wire does not make it a neutral wire. You, yourself, said that in an earlier reply.
This all started because you said the author of the article was wrong in referring to the COM screw as a brass screw. The author was correct. It is a brass screw. You said that the silver screw is the COM screw. I simply pointed out that there is no silver screw on a 3-way switch.
All of this stuff about the color of the wire and silver screws on a service panel are irrelevant to this discussion. And, besides, as Mike pointed out, we are simply talking about wiring a model RR here.
When I made my initial reply, I sure did not do it with the intent of annoying you. I was simply trying to add clarity to the situation.
Frank,
All my green wires go to frogs. That's how it is on my RR as a standard. Not sure where I picked it up, but others use it, too. Green = Frog <-- alien smilie in place of nonexistent frog smilie
Mike Lehman
Urbana, IL
I forgot to mention,the guy in the art. has the green wire going to the Frog.
In your third paragraph,you stated,that a ''Neutral Wire'' is not ever in a switch, I disagreed with you,Neutral being White colored wire., common is considered,the white wire. If you look at the art. he has a white wire,going to the left rail,which is ground,the black wire,going to the right rail,which is Hot,or positive,just like, your loco picking up positive,from the right rail,going forward. Take the cover off your service panel,in your house, You will see all the white wires running and screwed to a silver bar,all the black wires,run to your circuit,breakers connected to Brass screws,on both sides of the breaker and back to the circuit.
Brent,
Yeah, good tip on the cord wrap. That would work great with the epoxy, too, just smear on a little more. For now, I'm going to try to do without that, as it seemed overkill in this app. No vibration and your plane won't crash if something comes lose. But I will keep it in mind in case I run into issues.
There's no doubt the screw is dark or black on these 3-way switches. And we gotta remember weren't trying to wire anything but a model RR here. Reading those code books makes my head hurt, done enough of that as a building manager. In the end, the city building inspector has the final say, no matter what, so I count on him and my electricians to keep me out of trouble.
Frank, I find your reply confusing.
I was addressing the terminal screw issue on a 3-way switch, not the wire,
The COM terminal screw holds the hot wire, whatever the color of the wire coating. It is a dark colored brass screw to identify it as the hot wire screw.
Your third paragraph is not true. You are totally forgetting,how you would wire a three way switch,with armor cable wiring,before conduit, there were only two wires,black and white and none insulated plain wire, the white wire in a three way switch,was used as a current carrying wire in that situation and had to be painted black. You don't have to take my word for it. Check with The National Electrical Code, it has not changed. Before I decided to drive a truck, that is what I went to school for. MY first father in-law,was a Electrician,for 40yrs and I worked with him on the side so I could pass my Electrical Union Exam..Aside from that,I am reading right out of the book,in front of me..
Mike
Back in my old R/C plane days, we would have piano wire going into dowels the same as in your pic. Before we applied glue we would wrap a few turns of thread around the wire and dowel and then cover in glue. Doing that kept it from ever working loose.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
The terminal screws on a 3-way switch are all brass.
The two "traveler" screws are brass colored, but the COM screw is dark brass or even black colored to distinguish it from the traveler screws which interact with the other 3-way (or 4-way) switch. The COM screw carries power into the 3-way switch on the "hot" wire. The green screw is the ground screw.
Silver terminal screws are only used on outlets to hold the neutral wire. A neutral wire would never be connected to a switch, be it a single pole, 3-way, or 4-way.
My guess is that the author inadvertently omitted the word "dark", so it should have read, 'It's the terminal marked "COM", or the one with a dark brass screw'.
The code may have changed or the author was looking at what was in front of him. The Com on mine are black, too. I think it used to be White or that's just my flaky memory, but I suspect the code has been revised.
I forgot to mention the best thing about these, other than that they work great, is the cost is about $3 each. Hard to beat that.
The first one took me about 90 minutes. The second one I whipped out while cooking breakfast this morning so even faster. The next will start being in batches, so even faster and cheaper, because I'm gonna buy the contractor 10-pack of switches.
Only drawback for me is that the knob sticks out, so something to snag. I will be going back and putting a "bum" guard on each. You definitely want to set them up so that Normal position is in, as my knobs move out about an inch or a little more. I think I can lessen that by shifting the link attachment for the control closer to the pivot point of the switch. The article showed the control link that way and above the link to the turnout and mine are the other way around, so I can get a shorter throw and less protrusion by adjusting them there. You still have the knob even when pushed in, so need to keep that in mind when choosing the knob if your aisles are narrow like with a lot of us -- or are we just getting wider and the aisles aren't?
Mike,
I thought that was an interesting article. The only part that I found,that is not true, is when he was describing,the Electrical switch itself, He said the common terminal on the 3-way switch, (''It's the terminal marked ''com'' or the one with a Brass screw'') that is incorrect,,the white or silver screw is the com. the Brass is the ''hot'' screw. Per. The National Electrical Code and UL. and Green is ground. Other than that,it was OK.
I had heard somewhere of using ordinary 3-way electrical wall switches to make manual turnout controls. The November 2013 issue of MR has a great little how-to article by Mike Evans on pages 62-62. I needed some good quality controls for a few recently installed turnouts, so this was a well-timed article.
I did make a few mods. I used 1/2" poplar dowel instead of the specified 5/16". I found some knobs I liked at Hobby Lobby, but they come drilled 3/16" so need to use a larger rod for the handle end of things. I used some 10-24 threaded rod, which is a slip fit over the threads. I epoxy the knob on so this works great, but I needed a bigger dowel at the linkage side of things, thus used 1/2" dowels.
Here's how I attached the end link for the control rod. I drilled to the size of the wire about 1/4" back from one end, then cut a shallow groove in the side of the dowel from the hole to the dowel end. I prebent the hook, then epoxied the wire after it was pushed into the hole in the side of the dowel. This will be a robust connection.
[URL=http://imageshack.com/i/nem73qj]
[URL=http://imageshack.com/i/15hn81j]
The other end of the dowel is drilled in the center 5/32". This is a bit too small for the 10-24 threaded rod, so I wiggle the drill bit around in the hole to give it enough sloppiness to thread in.