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 Posted - March 09 2013 : 8:58:20 PM
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I need to learn about AC output and running accessory lights.
I am wiring up a display shelf that has 10 highway lights with two bulbs each, 4 stick-in-place lights for houses, two lamp posts, one billboard and will have possibly 20 more lights when I am done. I was hoping to run this all from one power pack.
I was working with a Tyco Pack with 20V AC and it stopped working and was pretty hot. I also have a Tech II transformer with 17V AC output, but the smaller transformer actually lists a higher AC output.
I don't really know the AC output of the lights. The highway lights had 14V AC listed on the package of one light. Does that mean it draws 14 volts from the transformer? The transformer only puts out 20 volts.
Is there a certain transformer I should use for accessories, or can I connect them to the AC terminals of my Tech II? How do people with large layouts power a lot of lights?
Any ideas or suggestions?
Mark
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Posted - March 09 2013 : 9:37:17 PM
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Resident electricians correct me if I'm wrong, but the overheating is due to too high of an amp draw for the power pack. You need a pack with a higher amp rating.
The 14 volt rating on your light means it can handle up to 14 volts; how many volts it is receiving from the 20 volts of the pack depends on how your lights are wired. If your lights are wired in parallel, it's receiving 20 volts. if wired in series, it's receiving less - divide 20 volts by the number of lights wired in series, the result is the number of volts each light is receiving.
Glenn
I was thinking of the immortal words of Socrates, who said, "... I drank what?"
Edited by - gmoney on March 09 2013 9:46:58 PM
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Posted - March 09 2013 : 10:08:04 PM
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Precisely! In a series circuit, if one load fails, the whole system fails. High amounts of amp will heat up stuff fast!
" Heck with counting 'em rivets, TRAINS ARE FOR FUN! Not called the Mad Scientist for nothing either!"
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Posted - March 09 2013 : 10:17:32 PM
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quote:Resident electricians correct me if I'm wrong, but the overheating is due to too high of an amp draw for the power pack. You need a pack with a higher amp rating.
The 14 volt rating on your light means it can handle up to 14 volts; how many volts it is receiving from the 20 volts of the pack depends on how your lights are wired. If your lights are wired in parallel, it's receiving 20 volts. if wired in series, it's receiving less - divide 20 volts by the number of lights wired in series, the result is the number of volts each light is receiving.
Originally posted by gmoney - March 09 2013 : 9:37:17 PM
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Correct, too much amperage will cause overheating.
An inexpensive, or sometimes free source for low voltage lights would be an old power supply from a PC. There's plenty of amps available to run your lights. Plus, running DC means that you can measure the amp draw with an inexpensive multi-meter in order to properly size your wire and fuse. Your ac power source on your train transformer can now easily handle all of the small tasks of switches and the like. Incidentally, always size the fuse to the wire.
Let's say you find a 300 watt PC power supply. I would imagine that you would want to use about a max 150 watts of 12 volts to be safe. There are other voltage outputs that add up to the rated wattage on the power supply, so you don't want to overload it. 150 watts is a LOT of tiny lights!
Here's some more info about re-purposing a pc power supply: http://www.instructables.com/id/Use-that-old-PC-Power-Supply-as-a-high-current-%2B3./
~ Dave
They're ALL toys
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Posted - March 09 2013 : 10:20:57 PM
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| I have the two street lights wired in a series. The other lights got too dim when wired in a series, so I just connected one wire to the wire from the + side of the power pack and one wire to wire from the - side of the power pack for each light. I guess that is my problem? But when I try to wire them in a series, they get too dim.
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Posted - March 09 2013 : 10:44:04 PM
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quote:I have the two street lights wired in a series. The other lights got too dim when wired in a series, so I just connected one wire to the wire from the + side of the power pack and one wire to wire from the - side of the power pack for each light. I guess that is my problem? But when I try to wire them in a series, they get too dim.
Originally posted by 59Chevy - March 09 2013 : 10:20:57 PM
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Wiring lights in series will split the voltage between the 2 lights.
~ Dave
They're ALL toys
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Posted - March 09 2013 : 10:52:58 PM
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Is it possible to wire my lights not in a series (parallel?) and keep them from blowing the transformer?
Is there a transformer that can handle 25-35 lights wired parallel?
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Posted - March 09 2013 : 11:17:58 PM
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You're confusing voltage and current, although they are interrelated. The Tyco pack probably puts out 20 volts because it can't supply much current, and as the current draw from multiple accessories increases that voltage reading will drop.
Current is the measure of electrical flow, and a typical GOW bulb draws around 50 - 60 milliamps. So if your current bulb count is 27 (based on your description) assuming a 60 milliamp draw from each gives a total current draw of 1.62 amps. That's quite a bit and more than a Tyco pack can handle (it can probably supply around an amp max). That's 2 or 3 old Blue Box Athearns hauling a heavy consist. The MRC pack can handle it, but it would be more accessory load than you'd want if you're running locos with it too.
With the amount of lighting you want, you should get a bunch of cheap transformers -- or even a few hefty wall warts -- and divide up the lighting duties amongst them.
The computer supply is a good idea, but I think they only have a maximum of 12 volts which will make most accessory bulbs quite dim.
The Tyco Depot
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Posted - March 09 2013 : 11:23:07 PM
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Most PC power supplies have +12 and -12. Going across both terminals is 12 volts. They're very versatile power supplies, very safe due to built in short detection and put out clean voltage.
~ Dave
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Posted - March 09 2013 : 11:44:55 PM
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quote:Most PC power supplies have +12 and -12. Going across both terminals is 12 volts. They're very versatile power supplies, very safe due to built in short detection and put out clean voltage.
Originally posted by RDC1Â -Â March 09 2013Â :Â 11:23:07 PM
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Yes, and it occurred to me that -5v and +12v will give you 17, but I'm not sure what the current rating is in that configuration. On more modern supplies the 5 volt rails supply less current.
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Posted - March 09 2013 : 11:48:03 PM
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quote:Most PC power supplies have +12 and -12. Going across both terminals is 12 volts. They're very versatile power supplies, very safe due to built in short detection and put out clean voltage.
Originally posted by RDC1Â -Â March 09 2013Â :Â 11:23:07 PM
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Correction, 24 volts.
~ Dave
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Posted - March 10 2013 : 11:08:26 AM
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Part of the problem is the Tyco power pack you're using. They weren't very good new, and after all this time, they are prone to overheating from the load. Now, most kids would only wire in a "few" lights, not many-many. And the Accessory power is still drawing current from the HO DC side as well, they're not separate power draws. It's cumulative, one AC input, then they split off the draw to each side, so if you're using way more lights, the DC side will see a downturn in output as well, and also heat up more due to the current draw from both sides. I'd find another power source if I was you, OR, get another Tyco supply, and use one just for lighting, and the other just for the DC for your HO trains. But they are really inferior power supplies, so anything more than a few lighted accessories and you're putting a tremendous strain on that pathetic power pack. I like MRC, even the vintage metal ones produced nice power, although I've never used them for accessories much. So, bottom line, either find a better power source, or use multiple supplies to cut down on the current draw on each one, if you insist on using Tyco brand supplies. That's my recommendation.
Jerry
Electronic Tech, HO train Collectorsseur
" When life throws you bananas...it's easy to slip up"
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Posted - March 10 2013 : 11:37:12 AM
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I had planned on using the Tech II for the power supply; I was just using the small Tyco power pack while working on it. I was just confused because the smaller one had a higher AC output listed than the Tech II.
I'll switch to the Tech II and see how it goes.
Thanks!
Mark
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Posted - March 10 2013 : 11:52:01 AM
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quote: I was just confused because the smaller one had a higher AC output listed than the Tech II.
Mark
Originally posted by 59Chevy - March 10 2013 : 11:37:12 AM
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Part of that is because of the higher voltage output, you can put more load onto it and the draw down will bring it down to 14-16 volts at full load. It's cheaper to wire the power supply for slightly higher voltage to adjust to more current draw, in other words. The transformer design determines the output, so by designing it with slightly higher voltage output, you can draw slightly more current from it by loading it up more. But it's a cheap way to do it, and overheating if you overload it is the result. A well-designed transformer has more windings for more current draw, but is also more expensive. Tyco probably figured they wouldn't play with it for more than a few hours at a time, anyway. I remember burning up a few power packs by using them for more than just a few hours. And an AHM Hustler motor, too.  They're just not suitable for any long-term use in my opinion, and while I have more than a few of them, I use MRC or my Tech II before I'll use a Tyco pack.
Jerry
" When life throws you bananas...it's easy to slip up"
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Posted - March 10 2013 : 4:26:13 PM
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change all bulbs to LEDs & use 5watts instead of 20 watts with bulbs 
That's what I gonna do with most of my loose & NOS accessories
Edited by - microbusss on March 10 2013 5:36:10 PM
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Posted - March 10 2013 : 6:39:23 PM
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| HOW DID I KNOW that Microben was gonna tell ya to change the lights to LEDs ??? And for me to molest NOS light poles is out of the question...
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Posted - March 10 2013 : 7:14:44 PM
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quote:HOW DID I KNOW that Microben was gonna tell ya to change the lights to LEDs ??? And for me to molest NOS light poles is out of the question...
Originally posted by walt - March 10 2013 : 6:39:23 PM
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Cause LEDs use more than 1/3 the power of a regular bulb 
Plus my friend is changing all his Xmas lights to LEDs
&  his power consumption dropped big time
Also he's using less plugs than previous years
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Posted - March 10 2013 : 9:51:00 PM
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I can understand the Christmas lights change.... I even use LEDs on any custom car / truck build I do... But reguardless of my electric bill, I could never butcher my Tyco or Life-Like light ups... The saavings just can't justify that in my mind....
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