[banghead] Keep in mind this is my first lighting attempt!!!
I have a line of lights with switches between the transformer and the bulb the problem is that when I break them up into sets, say 4 lamps on a switch the more switches I flip the duller the lights become, I’m using a 12V transformer with 12V lamps?
Does anyone have a wiering diagram I can look at for wirering four lamps to a simple switch, I’ve tried searching this site but have not found the topic I need, this site is just too big!
OK let’s start here: You should post a drawing of how you’ve wired these lights. Many of us will be able to find your problem from there. A pencil sketch will be fine.
From what I see above, transformer lead “a” goes through a toggle switch to one side of EACH of the four bulbs. The other side of EACH bulb goes to transformer lead “b”.This puts the bulbs in “parallel” with each other and in “series” with the switch.
My best guess is that you are using high current bulbs and asking for more current than the transformer can supply. Don’t keep doing that or you’ll overheat it - possibly destructively.
look for a loose conection between the bulbs and switches and between the switches and transformer. Any loose conection will act as a resistor and make the bulbs dim. Another thing is the mini toggles. What rating are they. Can they handle the current?
Check the amp rating of the transformer, the switches, and the amp draw of the lamps.
There is a limit to how much current the transformer can supply.
If you exceed the current limit of the switches they will act like resistors until they fail.
Add the draw of the lights together to determine how much you need from the transformer.
Wire size and length can be a factor as well. Are the switches and the transforme near the lights, or have you run a light wire all the way around the layout?
As always, good replies , I’ll check into each but what has me baffeled is that without the switches in between the bulbs and the transformer the lights worked fine , once the switches were added things went wrong.
The bulbs are 12 Volt as is the accessory coming off the transformer, the switches are 12 volt also and I’m using 20 gage wire at the moment, the longest run of wire is about 6 feet.
Hope these details help narrow my search for a cure!
Thanks again for helping out, you guys are the reason new bees stay with this hobby!
Current flow is measured in Ampheres (amps), or in this case, in milliamps (1/1000 of 1 amp).
My guess would be that the switches are too light. Try a heavier switch. SPST
If you want to see if the switches are the problem, turn on the switches one at a time until it starts to dim. Then use something conductive to short across the terminals of one of the switches, thereby bypassing the switch and see if it brightens. Or just put jumpers across all the switches, and see if the problem goes away. That’s all the switch does, is connect the two teminals internally.
If the switches are not the problem, then you must have caused a partial short or a loose joint somewhere during the installation of the switches. Check your solder joints and any place that the wires could rub on something conductive. Soldered joints should be shiney. If they are dull, resolder them. A cold solder joint is caused my movement while it is cooling, and can add resistance. That’s why you should have a good mechanical connection before you solder it.
Very light switches can be damaged during installation if you apply too much heat for too long.
I think it is really unlikely the switches are too light. I think the most likely thing would be that when you added teh switches you accidentally changed the schematic, and some of the lights are in series. Make sure things are hooked up the way you drew them, and that there isn’t a sneaky sire shorting something together.
How do you wire two bulbs in series but keep them on separate switches without using double throw switches? You could wire two bulbs in series on one switch, but only those lights would be dim. It would not change the others that were already on.
I would look for a partial short. If the voltage is being pulled down as you add lights, there is a load that exceeds the output of the transformer.
OK, your electrical schematic is correct. You have the lights wired in parallel, with the switches in series with the lights.
Things to check.
Somehow the wiring doesn’t match the schematic. Wires are tricky little devils, and they twist themselves out of your hands and hook up where ever they please. Double check all the wires, make sure they are going where they ought to go.
You have a loose connection. Wires ought to be joined with soldered joints or gas tight crimp connectors. Just twisting them together isn’t dependable.
Your transformer doesn’t have enough omph to light all the bulbs at the same time. The little trainset transfomers (power packs) might not handle even four bulbs, depending upon bulb size, other loads on transformer, etc. You can do a paper and pencil check if you can find the current rating on the transformer and the current required by the bulbs. Try googling on the bulb numbers and the transformer’s maker and model number.
Or experiment. Leave the switches out of the picture to clarify the issues. Wire one bulb to the transformer. Watch it light. Wire a second bulb and watch it light. Keep going until you run out of bulbs or the bulbs start dimming. If you find that the bulbs start dimming when you hook up bulb N, and just get dimmer and dimmer as you hook up bulb N+1, N+2 and so on, it’s a good bet the transformer only has enough omph to light N bulbs. On the other hand if yo
I figured it out by tearing everything apart and starting over.
First problem was ( I was using a 12volt transformer but not a train one, this one was from my scanner modified for a power source…NOT THE RIGHT POWER SUPPLY, so I got two that are for train sets.
Problem #2, I had a tiny bit of soldier flow and create a arc across the two pins on one of the switches.
Problem #3 I had basically melted down a switch from keeping the soldering gun on too long.
After correcting these things I’m now good to go.
I thank everyone here who helped me figure this mess out.
Some day I hope to be a good modeler and it will be because of the support I’ve found here.
If you read the thread on whether or not you need to twist your power or communication buss, you are aware that AC can induce a flow in nearby wires. In fact, that is how a transformer works.
A solder gun has a very large AC coil in the thick part of the gun. It enables it to heat up very hot very fast.
Be very careful using it around your electronic components. It probably works great soldering rail if you don’t leave it on there very long. But I would invest in an iron for small wires or anything that is within 6 inches or so of electronic devices like decoders or circuit boards.
glad to read that you have solved the lighting issue. While reading your post you wrote that you are using 22 gauge wire to power your lights. This got me thinking about the restrictions with regards to conductors. Conductors are measured by the north american wire gauge method and tables have been established with regards to the current carrying capacity of the wire. In the Ontario Electrical Safety Code book it states the following - all under ideal conditions.
20 Gauge - not rated amp
18 Gauge - 5 amp
16 Gauge - 7 amp
14 Gauge - 15 amp
12 Gauge - 20 amp
If the wire is overloaded it can pose a safety hazard because of the heat generated from the wire melting the insulation and potentially causing a fire. When wiring up 12 volt lights it does not take much to have some substantial current flow. Also when going any distance with such small conductor there is a voltage drop because of the resistance of the wire. This means that the the furthest light will be the least bright.
So it might be an idea to use some large sized conductors in your next lighting project. If you have any questions please send me an email.
While it’s true that overloading wiring can cause problems this isn’t too likely with 12V lamps unless you’re using something heavy duty (like commerical low voltage accent lights the pull an amp or two each).
I’m assuming you’re using 12V grain of wheat lamps. These are problem around 0.1 amps each so you’d need to have around 50 of 'em to be pulling 5amps. I doubt very much that a train set trainsformer is going to generate 5 amps at 12V. If you’re trying to do this you’ll have problems with the transformer (overheating, self-destructing, or possibly bursting into flame or perhaps just popping a fuse or triggering overcurrent protection if it’s a good quality power pack) long before you’ll have problems with your 20 ga wiring.
You seem to have figured out at this point that neatness counts when it comes to wiring. If you make a solder splash clean it up. Don’t use so much heat you melt components. Keep the wire runs as simple as possible. Use multiple colors for the various purposes - for example red from the + terminal and black from the - terminal (this makes it muh easier to see what you’re doing).
Oh, and those toggle switches are almost certainly rated for 5amps so I wouildn’t worry about them for that reason.
Good luck to you (and congrats on successfully troubleshooting your problems!)
Yah, I was really worried until I checked into this more, I’m using 30 tiny “Grain” style lights and the wire I’m using is heavier than the wire that is attached to the lights when they manufactured them so I believe that I’ll be OK and not burn my house down.
I did a neat and orderly job wireing everything up and used shrink tube around each soldierd connection.
I doubt I’m pulling more amps than the switch is rated for.
But the post on the wire gages was a reason to check into model wiering closer so it did serve a pupose other than scareing the be jeezes out of me. [:O]
Thanks for helping releave some of my fears over lighting up my layout.
sorry Red Horse, I did not intend to scare the “be jeezes” out of you. It was just to point out to you and everybody else that it is wise to keep in mind the rating of all aspects of the circuit. Switches have their ampacity marked quite clearly, wires have this strange AWG - American Wire Gauge number assigned. So I thought it might be appropriate to inform fellow modellers of the rating of the conductors that they use.
