Anyone have a source for cheap (from China) DPDT single coil LATCHING relays?
Thanks
Bob D
Mouser lists some.
Would W.W. Granger be able to help you?
You never stated coil voltage or load on contacts
Here is a single coil latching type with 12 volt coil and 2 amp capacity on the contacts
There are also single coil ratcheting relays as well
Granger may have them but I don`t want to pay the price of a Kato boxcar for each of the 10 relays I need.Those guys are always the highest priced of all the retailers for electrical/electronic equipment. I was hoping someone knew of an overseas retailer who had them for around $3,00 each. The coil voltage is 12VDC and the contact rating can be as low as 100ma. I need them to power leds for turnout position both on a control panel and between the ties.
Bob D
LION bought several of these at All Electronics, but they have not had any more for about 10 years.
Not sure how you are using these, but do you really need latching relays? Regular relays can easily use one spare contact for a holding circuit typical as used in motor starter controls.
I use this type of setup to control all my turnouts and they provide frog power, power routing and signal interlocking logic as well as directing power to the switch motor, panel lights and allowing as many push button stations for each turnout as you want.
Sheldon
This might get you started http://www.ebay.com/itm/Latching-Relay-single-Coil-12-Volt-/190880030042?pt=Model_RR_Trains&hash=item2c71561d5a
Sheldon:
Could you show us a wiring diagram of how the relays work in your system? Sounds interesting.
Thanks
Dave
Dave, I will try, and maybe you can help me. I have no real idea how to post a drawing on this forum. I can scan one of my drawings and put it on photo bucket, but they never seem to come out to clear.
I do not use any kind of computer drafting for that sort of thing. I took CADD years ago, but never really used it, and never took the time to learn any of these more baisc drawing softwares - they all take to long. As a draftsman trained the old way, I can draw something like that faster than I can open up a page on the computer to do it in.
But I will dig out one of the diagrams and see what I can do.
Sheldon
OK, this seems to be working:
The first drawing shows how two relays are used for a single stand alone turnout. Actually, one relay will work if you use a combination of NO and NC pushbuttons, but I prefer to use LED lighted push buttons that only come NO.
BUT, as soon as you pair two or more turnouts together, you only need one relay for each turnout and you can route control the whole interlocking or junction for one button route selection. The drawing shown is for a wye.
You can have as many push button locations as you want and the lights will change at all locations when the turnouts are thrown.
I use 24 volt 4PDT ice cube control relays. They can be had new in bulk for about $3 each or found used for half that. Threy are industrial machine quality and last forever in this sort of service.
Sheldon
Sheldon
You and I are in the same boat as far as putting graphics into a post. The last time I did it I simply drew the diagram on a piece of paper the old fashioned way, photographed it and put it on Photobucket.
Maybe somebody here can give us an education on how to do it in the modern age[swg].
Dave
EDIT: Apparently you were posting the diagrams while I was writing my post.
Thanks for taking the time to do that.
Dave, you are most welcome. I was just happy the scans came out so good.
These same circuits can be configured to do any track arrangement so that one button aligns all the turnouts, powers all the frogs, direct the block power through the interlocking if you use DC like me, and provide a logic path for the interlocking signals. One 4PDT relay per turnout.
Maybe a little more work to some people, but way cheaper than stationary decoders and computers.
Sheldon
Please explain what you mean by “LATCHING relays”. ANY relay can be made to “latch” itself, through its own contacts. If you mean “magnetic LATCHING relays”, there has to be either (1) a second coil, to UNLATCH it; or (2) a way to REVERSE the polarity of the coil, to unlatch it. Neither of these appears on your diagrams.
/Lone
Respectfully, my diagrams do not use latching relays, I was suggesting to the OP that he do exactly as you suggest, using a holding “contact” on the relay.
The OP asked about latching relays, some are twin coil, some use reversed polarity, he did not indicate clearly what kind he wants or how he will wire them.
Sheldon
Hi Sheldon:
I hate to look like the dummy that I am, but could you please identify the various components in the diagrams? I understand the push button switches, the turnouts, the tortoise, and the LEDs and resistors but I don’t recognise the symbols labelled “all”, “local”, “a”, “b”, “c”, “R1”, “R2”, or “R1 circled” and “R2 circled”.
The answers are likely very obvious but I barely passed grade 9 electricity so it takes me a while to figure these things out. It recently took me nearly three hours to figure out what I had done wrong when hooking up the headlights on my railtruck project. (turns out I had done just about everything wrong![D)][(-D][(-D])
Thanks for your patience.
Dave
No problem Dave.
R1 = relay #1, etc, the circles are the relay coil, the gaps are normally open contacts, the gaps with slashes are normally closed contacts. The “state” of all contacts is show with no power applied.
Are you familar with the term “form C contact”? That is a double pole switch, feed in, two possible outputs. Even though small relays use that kind of contact, the normal control drawing method of showing them is the “gap”. If you look at the first drawing at the two contacts close to each other marked R2, that would be one “set” on the relay. In other cases not every terminal on the relay gets a wire.
Local stands for local panel, the contact marked local at the top left is for an interlocking circuit that allows the dispatcher to prevent local control of turnouts by the train crews. The rest of that wiring is not shown.
The contact marked “all”
Hey Sheldon!
Thanks for your prompt reply. Now I understand the diagrams much better.
As for learning, I think model railroading is a learned science as well. In fact it involves many learned sciences, all of them very interesting!
Dave