Hi All,
I'm having problems with blocks. I have 4 blocks on my layout and i have them wired and set to the same polarities and every time I pass an engine over the insulators from one block to another I fry my potentiometer.
Everything has been wired, checked and double checked and I can't figure out why this keeps happening.
Here is a rough wiring diagram that goes to each of the 4 blocks.
Note: the switches are actually SPDT and DPDT switches for power and polarity.
Thoughts??
The picture did not make it here. You need to use a site like photo bucket to post photos here.
You missed the first message in the General Discussion Model Railroader forum.
There is no way to fry a potentiometer that I am aware of. The overload in the DC control should trip first. Mine have a pot controlling a power transistor and circuit breaker after the transistor.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
If the polarity is the same between blocks, then nothing bad should be happening. If there is no reversing loop involved, you have made a mistake in wiring. Your rough drawing may show how you think it is wired and not how it is wired. Get yourself a 12 v bulb connected to a couple aligator clips and do some testing.
Henry
COB Potomac & Northern
Shenandoah Valley
Hi,
Read through this and see if the answer lies within.
http://www.nmra.org/beginner/wiring
Are you using common rail? Do you have more than one cab?
The polarity should only change at the power pack (transformer) unless you are including a reverse loop.
Good Luck, Ed
BigDaddy If the polarity is the same between blocks, then nothing bad should be happening. If there is no reversing loop involved, you have made a mistake in wiring. Your rough drawing may show how you think it is wired and not how it is wired. Get yourself a 12 v bulb connected to a couple aligator clips and do some testing.
Where is the drawing? Must be a different method that I am not aware of for posting photos.
Sorry about that.
Here it is.
I never said I saw the drawing. Newbies have trouble posting pics in all the forums of the Internet. At least he stayed away from the CAPS LOCK KEY.
A guy that likes wine and trains, deserves a break
Why doesn't the power supply have circuit protection?
Jim
the link is not working for me?
I suggested to the OP to read the first post in the General Discussion, Model Railroader forum but suspect it did not work for whatever reason.
http://cs.trains.com/mrr/f/88/t/249194.aspx
The easiest way to share a picture here is to see it on a website, right click on it, click COPY, then paste it here. (Ctrl+v)
It sounds like the OP is not using an electric train transformer and is just hooking up a power supply to the tracks and using a volume knob. It also sounds like he might have one set of wires reversed.
LION has complicated wiring. To make Complicated even more obtuse here is plan of LION.
LEFT rail is connected to GROUND. A hard ground that connects through to the building grounding system. Failure to have a good ground at this point will allow stry voltages on what is essentially a floating common, which is not at all the same.
The right rail is divided into blocks by insulated gaps. Put +vdc on the right rail, the train moves forward, put -vdc on the right rail and the train moves in reverse.
The leads from each block go to your selector, where you may select which power pack is controling that segment of track. A SPDT switch with or witout center off will celset between throttle 1 and throttle 2. Interlocking gang switches such as the LION used to use would select between throttles 1 thru 6.
When wiring the power packs put the reversing switch in FORWARD, and TEST it to see which terminal connects to the selector switch and which terminal connects to ground. It really does not matter either way works, just relable the switch as to which way is in fact forward, but here it gets critical, all of your power supplies must be arranged identically otherwise the engine will short the system when it crosses the gap.
Now you layout is not as complicated as anything that the LION would build, so trouble shooting it should be easier. You cannot really use a test lamp as it will tell you the presence of voltage, but not the polarity of the voltage. You need two lamps each preceded by a rectifyer, so that one will light up if + voltage is found and the other will light up if - voltage is found.
If you did not make the LEFT rail ground, as your LION has suggested, any other ground will do. LION has electrical outlets all around the layout of him (this way him needs no extention cords on the floor), and since him used EMT conduit to connect these outlets (and to use as a handle to lift him self up should him be so misguided as to kneel on the floor) Him (or you) could use that conduit as your ground for testing your tracks. + voltage should be on the right rail and - (or zero, if grounded) voltage should be on the left rail assuming your power packs are set to Forward, and are wired correctly. Use your selector to choose between power packs, the position of + and - should not change.
Clear?
It is clear to the LION, but then maybe you are a primate, and are not of felid kind.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS