auto block system relays, rectifier, etc

 

Thanks, I have noted proper credit so I get it correct next time. I used to be able to remember these things.  

 

Automation Direct has 12 volt AC relays in SPDT, DPST, 3PDT & 4PDT. Linking to the relays here has failed in the past, but if you got to their site and drill down through the menus to the General Purpose, 15A, (781/782/783/784 series you will find them. Lots of nice features as well. Sockets are available also (links from the relay pages).

 

The menus would be:

Relays / Timers > Electro-Mechanical Relays > Square / Cube Relays... > General Purpose, 15A (781 / 782 / 783 / 784 Series)

 

 

That twin diode circuit from 1962 will work to run two trains, but it doesn't do what was originally requested which was the auto start and stop.

That observation has already been made several times.  Since you have a circuit that does what was asked for why don't you share it with the group?

If you message Bob, he'll send it to you you. It was printed in a "klassic" publication that kind of precludes sharing it in this forum as he presented it.

I had this at my house for a bit. Using insulted center rails, pressure, & at other times, insulated rail triggering 12volt relays. When activated by the toggle switch, turnout "A" auto derailing, throws turnout "B". Green=B straight, Red is B diverted to a turn. Another toggle switch(not shown) controlled a power jump to the outlined "stop" sections(blue,green come into play one direction, purples the other, but all were not active)

I added the blocks from memory, the blue sensor and stop were to the left a bit more after adjusting for timing.

 

It was fun. Started as a single train route reversing on itself, with an optional small oval, away from the more active area.

Then I started to want two trains at once.

 

 

 

 

Edit: were not active

Dallee has an auto control system, more complicated, but, if it works as well as the Stop and Go trolley system it should be reliable.

Two Train Automation with Momentum

Wiring diagram

 

Maybe I am the only one with this challenge but when I look at the illustrations I can't make sense of them based on looking on an actual relay.  I want to do this but I can't for the life of me figure out what goes where on a dpdt relay.   3 vertical inputs on each side and one horizontal on each side and one confused person.

Post a picture of your relay please.


Sent from a smart phone....please excuse the brevity and any typos

I would post a pic if I knew how to do that.  I posted them to my profile but I can't for the life of me post them in this thread.

Here is a spec sheet on the relays I posted above. There are diagrams and terminal markings. Also on most relays of this type the terminals and a little wiring diagram is printed on one side of the relay. Take a look and see if this helps.

 

Ask if you have questions and I will try to answer them as best as I can.

Thanks.  I think I will pick up a few of these.  

 

http://www.automationdirect.co...,_Plug-In,_3A_-_15A_(78x-z-_Qxx-z-H78x_Series)/General_Purpose,_15A_(781_-z-_782_-z-_783_-z-_784_Series)/781-1C-12A?showReviews=true

 

 

i want to wire a loop and have two trains running at one where the leading train kills the block behind and activates once it leaves the block.  

 

For some reason that relay site won't link here? Many have tried and many have failed! Either follow the link in my post above following the menu structure I posted or when you get to the search box from bdobson's link use 781 relay for your search. Following the menus from the main page gives a bit better of a page layout for some reason also?

 

Those really are nice relays, IMO. They come in quite a few coil voltages as well, some harder to find ones. Lots of features, the socket locks the relay in place and has a place for labeling on the lock bar. There are even plugin MOV and diode modules available for them. Free 2 day shipping on orders over $49 also. (No, I don't work there, just like the relays. )   

 

In the diagram above showing running two trains through diodes if both throttles aren't set to the same voltage a portion of the transformer will be shorted through the two diodes.

Relay info to at least check out. In simple terms, diodes here, help a relay from "fluttering". (used on ac & dc alike, some are built in)  http://en.wikipedia.org/wiki/F...e:FlybackExample.GIF

 

 

common is not always = to a ground in electronics, it can cover different meanings. Even with power, common does not necessarily mean negative, and negative doesn't mean always mean ground.  It has to be taken in context. In a relay common means the one lead common to the two positions of the relay points, NO & NC.

A relays electrical mechanics, are a simple electromagnet solenoid (linear motor) (a coil of wire around a loose nail).

I just checked out the relay specs above. I sure could have used those plug in diodes on a few coin-op machines. (if you have a coil issue, its normally that diode, or the switching components just before it)

The slight offset of pins on the center rail, and green isolated rail is to account for wheels activating relay before a roller can make un-broken power You can divide this easily too. Energizing connect pink. For a dead stop, remove pink wire

and if you choose only 2-3 blocks, maybe this

If you run lighted/operating cars/cabooses, etc.. LED lights with a good capacitor might be needed. Or something going to the motor(diode) to slow them down till voltage at the cars achieves a "normal level" on a "slowed" track.

Ebay is your friend for small parts, just search 12 vac relay, and look for at least 5 amp contacts.  Free shipping and buy it now are also good in most cases. 

I would prefer the open style versus the kind that plug in.

 

 

Example

 

http://www.ebay.com/itm/Magnec...;hash=item58b2ad5850

 

 

Charlie

Curious question. How come nobody seems to want to use the Potter and Brumfield KUP-11a15-12ac relays anymore? Industrial strength, these don't need a bridge rectifier and work great off a small AC transformer. I have 10 of them driving signals and have never had an issue in 15 years. Newark and Mouser stock these and their bases.  

Two reasons.

 

#1: $12.72 is pretty expensive for a relay.  Add the cost for a base and it's pretty steep.

 

#2: With a dc relay you can add a capacitor to eliminate chatter.

 

It is interesting to note that this original posting has generated as expansive a discussion as that late 2014 discussion on the merits of battery operation for OGauge. Looks like model trains are not all that simple.

And the amount of that offset should be more than "slight" if you are running certain engines like the early post-war Alcos and GP-7’s.  On the Alco’s the center rail pickup is 5” back from the front axles.  When running post-war Geeps short-hood first, that  measurement is 8”.  So in that case you need to offset the center-rail insulating pin at least 8 inches back from the outside rail insulating pin to avoid the engine stopping completely at low speeds.  How did I learn that?  The hard way, of course!

 

Bill

P&B were prevalent in coin-op, and large industrial applications. Coin ops can do 10,000 cycles in a week. If I had the cash option, it would be my 1st choice. 

And another 9 for a screw base. So for about the same price as the Train Electrics AC DPDT you get a Heavy Duty industrial rated relay? It still amazes me how an OGauger will spend Kilo bucks on a scale essentially handcrafted Locomotive, but cheap out on the essentials. Its not too long afterwards that they post up that they can't understand why said locomotive runs disappointingly on their layout.  

Whatever floats your boat.  P&B isn't the only relay that is reliable, and I prefer DC relays for the reasons stated.

 

Potter and Brumfield KUP-11a15-12ac

Mechanical endurance 10x106 ops.

 

Then I go to the American Zettler model that Jameco is selling for 99 cents.

 

AMERICAN ZETTLER  AZ942-1CT-12DE

Life Expectancy Minimum operations
Mechanical 1x107
Electrical 1 x 105 at 10 A 277 VAC Res.

 

So, I get a relay that has an expected lifetime 10x the P&B one, and instead of $12, I get it for $1.  What's not to like?

 

There's more than one way to skin a cat.

 

You go with what you know. Industrial HVAC industry relied mostly on P&B too.

P&B may offer an identical relay to the AZ.

I think we are also comparing two case styles with different industrial classifications.

But...Now I know something new, GR John likes AZ.

How old is American Zettler? Did they once have an inverted diamond-like triangle logo? Actually seems familiar, but not as prevalent.  

 

 Aluminium, or Aluminum screws to hold the base?

It seems American Zettler is a pretty robust company with a diverse product line.

 

Truthfully, while I understand the desire to have bulletproof construction, the primary selection criteria I use is the functional aspects.  For signaling, DC relays offer me more flexibility, the ability to eliminate contact chatter is big in my book.  Our modular club modules have a bunch of salvaged DC relays from industrial controls, we've never experienced a relay failure, and I seriously doubt I'll live long enough to see one.  Any decent quality relay will probably stand the test of time for the types of applications we're doing.

 

As a counter-point, I had a Potter & Brumfield T-92 Relay DPDT 120VAC 30A T92S11A22-120 in my power panel to switch my generator in, the coil failed in less than a year, maybe a dozen or two activations at most.  Any part can fail.

P & B is owned by Siemens. I used to work for Siemens, different division. We used Idec relays, P & B were too expensive. Go figure? The Idec's were very reliable, about the only failures were when someone (usually new) tried using one to start a motor directly. The contacts close, never to open again after that first start up. Don't ask how I learned this.  

 

Anything can fail is right, just like our trains. Most are quite good and well designed and built, but as you say, any part can fail at any time.

 

I am fairly new to DC relays (everything we did was AC) and also beginning to like that as a power source and for relays. No chattering is nice.

GunrunnerJohn,

 

Do you have a suggested vendor/part number for a capacitor to eliminate DC relay chatter?

Kirk, you can use any generic electrolytic capacitor once you have a DC supply to the relay.  To be honest, it's such a simple circuit that I've never drawn an "official" diagram.

 

A diode, a 10 ohm resistor (inrush limiting), the capacitor, and the relay.  If you run DCS locomotives, I add a 22uh choke in front of the diode.  The capacitor is sized for the coil current of the relay, the more coil current, the larger the capacitor.  Typical values would be from around 220uf to 1000uf.