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Posted By Greg Elmassian on 25 Aug 2009 09:54 PM

I sense something else here, are you wanting to challenge that it can handle that much current? Do you need that much current?


No, nothing like that.


All I'm saying is that the trip current and the maximum switching current the unit can handle are two totally unrelated parameters.

Obviously, the switching current the unit is capable of should be higher than the maximum trip current that can be programmed, but it will only be higher if the output switching devices can handle that.
Not that this needs to be an issue - there are plenty of inexpensive high current MOSFETS available, but you can't assume that if the unit is set to a trip current of 19.1 amps (or whatever), that the output devices automatically handle 19 amps.

The trip current is set by either measuring the voltage drop across a transistor or with a voltage comparator or a current sensing transformer or or or, lots of other ways, where as the switching current depends solely on the output devices used and the heat sinks.

All I see in the manual are different trip settings up to 19.1 amps - one would hope that the output devices of the unit can switch also switch at least that current, but unless that is specified, there is no guaranty that this is the case.


Regards, Knut
 

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OK, now I get "your" definition of "switching current" as applies to this device...

Yes not specified and not guaranteed. It's at least 19 amps I would surmise, but have never tested over 11 amps

The engineer would be an idiot if it was exactly 19 amps. Based on my experience with the device and and my friends who use them, I will not lie awake at night because I don't have the specification or guarantee.

So far it has delivered what it promised. I have the optional heat sinks on mine, recommended for operation over 9 amps.

Regards, Greg
 

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I don't understand why you think this is "my" definition of "switching current".
There is some device(s) that reverses the track polarity, relay, MOSFET, transistor whatever...and it has a manufacturer specified current rating that it is designed for un der certain operating conditions some of which (no heat sink or different types of heat sinks) I mentioned earlier. Temperature is another one.
These are all industry standard definitions - nothing that I invented.

I just like to know what I'm buying, especially when it comes to electronic devices in Large Scale.
And unless you have some specification from the manufacturer to point to, you don't have a hope getting anywhere with a complaint if the product doesn't perform as expected.
Nothing to do with this particular device other than that there are no specifications listed at all.
 

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Knut, as I said, I'm not lying awake at night about this. It works, and works to my expectation, and two people I know well have had similar good experiences.

You wanted "switching current" not to mean the "current switched", but the MAXIMUM current capability... so you could have been more precise in my opinion.

But don't worry any more about it, go buy the Massoth for what must be at least twice the price. You will be helping the economy (of Germany I guess) .

Buy what you want. (are you really buying one?) I have the DCC specialities one, it works.

If you want nice specifications on all your G scale electronics before you buy them, then that's your personal decision. It will be a cold day in h**l before this is the standard in G scale. This is not rocket science, and we are not buying rockets. (at least I am not buying any rockets!)

Regards, Greg
 

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I think I'll pass without any more comments.

But just to be clear - I'm not buying the Massoth unit or promoting that in any way. The only reason I mentioned it was because it will handle analog reverse loops which none of the others will.
And that after all is the topic of this thread.

Regards, Knut
 

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I applaud all of you electronic geniuses. However, it seems that this topic is back to where we started, the simplest route to wiring a reverse loop.
 

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Isn't that great? We managed to steer it back to the original topic, and find the answer to the original question. The answer is the Massoth autoreverser.... of course not the cheapest, but the simplest was requested.

Greg
 

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Posted By toddalin on 06 Sep 2009 12:24 PM
Posted By Madman on 06 Sep 2009 10:03 AM
I applaud all of you electronic geniuses. However, it seems that this topic is back to where we started, the simplest route to wiring a reverse loop.




My way.

Can be made to switch any amount of current (relay dependant). Works with simple track power, Aristo Revolution, DCC, and ???. Can be implemented using internet surplus parts for ~$10. Sounds like the clear winner to me.
 

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Simple is buy one and hook it up to the track in my interpretation of the word.

Since yours has to be made, and is not off the shelf, it may be technologically simple, but it's not simple to do for the average joe. It's definitely the cheapest, and what I would do if I needed one.

Regards, Greg
 

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Well Greg my friend I have to say that looking at your page, it's not quite as simple as plug and play--you need to add heat sinking to account for the higher amperage, which means ordering parts and finding ways to attach them.

That being said, it still looks easier to me than Toddallin's analog solution, which I frankly would have a very hard time installing. That's my fault, not the solution's fault.

Now that I have DCCi installed, and it seems to be working well (no time to give it a thorough test yet) I'll have to set up a wye or a loop eventually.
 

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Actually I am not using the Massoth, which seems the only solution for DC.

The PSR-AX is much less expensive DCC only, as are most autoreversers. I added the optional heat sinks in order to go over 10 amps, again something most people would never need. I also added the optional sounder. Most people don't need those options, and making them optional (although it takes 5 minutes to add them) keeps the cost down. Remember that these can be used for smaller scales, so few people in the smaller scales need the options and they are looking for lower prices.

There's an entire series of this product, with optional switch controllers, etc.

The Massoth, which is the only off the shelf solution for DC autoreversing, is just 4 wires, power in and power out to the reversing section, as most autoreversers.

Regards, Greg
 

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I personally like the solution with a single latching relay best.
I haven't tried it but I have seen that concept published in a few places and a friend of mine in Austria is using it.
It requires a bit of wiring but is relatively elegant and inexpensive.

Another possiblity that just came to mind:
Use the LGB reverse loop set which requires no wiring at all and add a simple DPDT relay to automatically reverse polarity when the train is in the fixed polarity reverse loop section.

Knut
 

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Knut, wiring is wiring... you need wires to run to the track. In terms of applying a circuit, I think insulating the section of track and hooking 2 leads to it in any polarity you want is simplest.

That's the beauty of an autoreverser, you supply it power, and it determines the polarity. No wiring other than connecting to the track, no polarities to be concerned about.

That is simple.

Regards, Greg
 

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Greg -

I don't really understand your comments. Which part of my post are you commenting about?

The latching relay one is just my personal preference considering number of components, cost and complexity of wiring.

The LGB reverse loop set plus reversing relay is just another idea that came to me.
You can of course wire the diodes yourself instead of using the LGB set.

If you only use the LGB set then you don't have to do any wiring at all for the reverse loop modules but you need to reverse polarity manually when the train is in the reverse loop.
Adding the relay to do that automatically still requires only two wires to the track plus the sensor to drive the relay but of course you have to cross wire the DPDT contacts.

There are many different ways to accomplish the reverse loop with DC, with DCC there are only basically two, a module that triggers on a short circuit or a module that is triggered via some sort of track contacts (no short circuit).

Knut
 

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Posted By krs on 07 Sep 2009 08:56 AM
I personally like the solution with a single latching relay best.

Knut

The latching relay you've shown is a propriatary unit. I have NEVER seen a 4pdt latching relay. Most are 2pdt. Also, you'll not find a latching relay capable of switching more than a few amps. The one you've shown is made for small scale stuff.
 

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Sorry Knut, you said you prefer.... not that it was simpler...

And in DCC, you can do anything like DC if you want... you can pretend it's DC and flip polaritiies, use relays, go completely nuts and make it really complicated. Therefore you have more options in DCC, they are just more of a pain, but they are options.

The DCC autoreverser is 4 wires period and no extra hardware. Saying that adding an LGB relay is not wiring is not really fair.

Anyway, this is starting to get boring... enough already... so I'm not coming back to this thread, the user has lots of options and there is a DCC autoreverser.

Regards, Greg
 

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Posted By toddalin on 07 Sep 2009 01:53 PM
Posted By krs on 07 Sep 2009 08:56 AM
I personally like the solution with a single latching relay best.

Knut

The latching relay you've shown is a propriatary unit. I have NEVER seen a 4pdt latching relay. Most are 2pdt. Also, you'll not find a latching relay capable of switching more than a few amps. The one you've shown is made for small scale stuff.


Not sure how you decided that this was a proprietary unit, but the diagram I put up was only to show that concept - I said so right in the post.
As to you NEVER having seen a 4PDT latching relay doesn't mean they don't exist.
I just took one quick look at Digikey for instance - they show them in 4PDT 5 amp and 10 amp versions and in a variety of coil voltages.

The 5 amp version is almost $20.- and the minimum order quantity is 20, but Digitrax is only one supplier. There are many others.


Mouser has a 5 amp version where they have 62 in stock and the unit price is $18.60.

This unit http://pewa.panasonic.com/pcsd/prod...eng_nc.pdf


But one really needs to design the circuit first before looking for relays.
Might be cheaper in the end to use a normal relay with a Flip-flop at the front end.
 

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Posted By krs on 07 Sep 2009 07:15 PM
Posted By toddalin on 07 Sep 2009 01:53 PM
Posted By krs on 07 Sep 2009 08:56 AM
I personally like the solution with a single latching relay best.

Knut

The latching relay you've shown is a propriatary unit. I have NEVER seen a 4pdt latching relay. Most are 2pdt. Also, you'll not find a latching relay capable of switching more than a few amps. The one you've shown is made for small scale stuff.


Not sure how you decided that this was a proprietary unit, but the diagram I put up was only to show that concept - I said so right in the post.
As to you NEVER having seen a 4PDT latching relay doesn't mean they don't exist.
I just took one quick look at Digikey for instance - they show them in 4PDT 5 amp and 10 amp versions and in a variety of coil voltages.

The 5 amp version is almost $20.- and the minimum order quantity is 20, but Digitrax is only one supplier. There are many others.


Mouser has a 5 amp version where they have 62 in stock and the unit price is $18.60.

This unit http://pewa.panasonic.com/pcsd/prod...eng_nc.pdf


But one really needs to design the circuit first before looking for relays.
Might be cheaper in the end to use a normal relay with a Flip-flop at the front end.




You could use 10 amp relays and build my schematic twice over for less than the cost of one of those relays alone. Besides, those don't even trigger as per your schematic.
 
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