rav4 If I am dividing my layout into two boosters for power & isolation ,why then would I wire it as shown ?
I believe that the premise of the example shown in that article assumes that the railroad was pre-existing with blocks and had the capability of being operated with two DC controllers. So what they were originally trying to show was that you could remove the DC controllers and connect the new DCC system in place of the original DC controller.
Normally with a DCC installation they recommend that you have a separtae power bus running around the railroad and tap off from that bus at set distances along the line to minimize voltage drop. But when you connect the DCC system to the block toggles, the power is distributed to the track at the same points where the DC power was fed, typically at one spot in each block. Of course, this could be problematical if the wiring from the block toggles to the railroad are in long runs and the owner has used the typical free (junk) wire he has found around the house. But that's another topic.
So, then what they tried to show was that if you needed another booster you could add that to where the other DC throttle was. At that point, if you throw half the block toggles one way and half the other, you would have two power districts. Now, assuming that your railroad was a straight line and the block toggles were in sequence on the panel, what one would logically do is have the left hand toggles all fed from one booster, and the right hand fed from the other. If it were me and I had something similar to what they showed, I would handle it differently. I would physically cut the power feed halfway between the two sets of toggles and connect the DCC boosters separately to each set. That way all the toggles get moved the same way to power a block, and there is no chance of someone throwing the toggle to the wrong booster.
Now, if you are starting from scratch, then the whole above discussion is moot. This is because you could potentially have no block toggles. This is because you would be tapping power off the bus I mentioned above. And if you think that there is any way that your railroad will grow to such jijantic proportions that an additional booster might be necessary, I would install two buses to minimize confusion later. You can always install a jumper between the buses initially and then remove that later when another booster was added.
Hope this was helpful.
Regards
I agree , it is a bad idea , one shorted dpdt switch can be a disaster . If I am dividing my layout into two boosters for power & isolation ,why then would I wire it as shown ? I do appriciate your input it really is helpful , thanks
rav4 thanks Jeff, you explained it perfectly now I can see why they are used. up for dcc, down for dc that says it all . Thank you very much , rav 4
thanks Jeff, you explained it perfectly now I can see why they are used. up for dcc, down for dc that says it all . Thank you very much , rav 4
That is not what the article you referenced indicates that they are for. What the article was showing was how to convert a DC railroad to a DCC operation by replacing the DC throttle with a DCC source. The only reason that the other side of the DPDT switch was used was in case you wanted to separate the railroad so that it could be powered by two boosters. As a matter of fact, I believe that the article specifically recommends not using DC and DCC at the same time.
If you are a solo operator and are diligent about disconnecting your DCC stuff when you want to use DC, yes it will work as Jeff described. However, if you have guests over and are not diligent, they could inadvertently throw one of those block switches the wrong way. And if a DC powered engine crosses over the block boundry, you can backfeed DC into your command station and boosters.
There have been many threads on this forum which suggest that doing the DC/DCC toggle switch thing is a BAD idea.
DarickI think in that article, The DPDT switches are there for DC operations. In that example, I think they are saying there are 4 block and 2 throttles. Just replace the throttles with Boosters, and set the DPDT switches for block A and B to one booster, and C and D to the other booster. The example is just replacing a current DC operation without changing the wiring. I hope this helps, and anyone, correct me if I am wrong.
I just looked at that article, and you are correct. The article states that "if you operate enough trains on your layout to require mutiple DCC boosters, you can add a second booster in place of another throttle. You can then divide the layout into two sections by setting half of the blocks to one booster and half to the other."
There was no intent to switch the blocks between boosters.
My layout is set up much the same way. It has 16 blocks all connected to the control panel through DPDT switches. Up is for DCC and down is for DC.
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I am new to DCC, reading the Jan 10 issue of model railroad magazine ,pg 78 fig 2 shows 4 DPDT sw's controlling blocks A B C & D. from two seprate boosters, if I am in the up position I will feed from booster # 1, if I am in the down position , I feed from booster #2 . my question is, why would I want to feed from either booster ? if I have a short in one block that is fed from booster #1 , I would not want to switch to booster # 2. what is the purpose of these DPDT sw's ?