# AC or DC - HO dumb question sorry...



## novice (Feb 2, 2011)

I purchased a few things recently and one of the HO track groups came with a transformer.

On the transformer it has 2 sets of connections one for AC and one for DC. 

My dumb question is: How do I know which my train is? I think if I hook it up wrong I could destroy the train yes? I'm stopped at this point scared to hook it up Lol

Please help and thanks in advance.


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## tankist (Jun 11, 2009)

your train 99% DC. you connect DC output to track. AC is there for accessories


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## novice (Feb 2, 2011)

Wow that was quick - thanks tankist.

Moving forward


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## penlu (Dec 9, 2010)

the only "dumb" questions are the ones that are not asked!


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## Reckers (Oct 11, 2009)

Precisely. Novice, on this site, we pride ourselves on helping others get started. Everyone here is a beginner---some just began a little earlier. Please don't feel inhibited about asking questions or apologize for doing so. The question you posted will probably get read by about 20 people, today, who will mutter, "So that's how it works!"

Nice to have you join us,


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## novice (Feb 2, 2011)

Thanks for the responses everyone...

It's great to be somewhere and part of a group that doesn't snub their noses at those of us just starting out. Hopefully, I'll be able to one day return the favor and help others as well.

I've been on a few other forums which while there were some extremely helpful posters (I notice a few of them here actually), others were let's just say a bit "less than enthusiastic" in having learners as part of the forums asking questions.


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## tjcruiser (Jan 10, 2010)

Novice,

You're always welcomed here. Bit of quick background ...

DC motors are made with a coil-wound armature that spins within a set of fixed, permanent magnets. Because the polarity of the magnets is a constant, one needs to feed DC power through the motor to have it run. AC power can easily fry a DC motor. Most modern DC locos have this motor housed in a little metal can ... hence, the term "Can Motor".

AC motors (traditional ones, without internal rectifiers ... sidebar discussion) have the same coil-wound armature, but it spins within a magnetic electric field generated from a 2nd coil winding around steel plates. The magnetic polarity of this "field" fluctuates +/- at the 60Hz power cycle. Interestingly, an AC motor will generally also run on DC power!

Cheers,

TJ


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## Reckers (Oct 11, 2009)

Translation: use DC unless you branch out into something more exotic, like S scale. *grins* Then ask somebody on here before you run any juice to it! That aside, we like new people and we like helping new people get started---ask anything you want and don't be shy about it. 

Oh! And the most important thing---never let steel wool anywhere near your trains, and never clean track with sandpaper!


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## novice (Feb 2, 2011)

Thanks everyone - one thing I am not is shy.



Reckers said:


> never clean track with sandpaper!




Too late.

I cleaned most of my O with a dremel sander.


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## penlu (Dec 9, 2010)

I understand about not using steel wool... little shreds get sucked up into the engines and ruin the motors. But why not sandpaper? (I've used emery cloth)


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## novice (Feb 2, 2011)

penlu said:


> But why not sandpaper? (I've used emery cloth)


From what I read... after the fact, it leaves digs in the track that easily rust and fill with crud.


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## penlu (Dec 9, 2010)

That's kinda what I thought it might be. Guess I'll put the belt sander away! LOL!


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## novice (Feb 2, 2011)

LOL, wish I knew then what I know now. I almost put the grinding wheel on the dremel.

I know you're supposed to use the scotchbrite pads, but the rust wasn't coming off no matter how I scrubbed.

Hopefully, I've done enough damage and can move forward. I hope I don't have to replace all that track.

I wonder if the chemical rust remover will work better?


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## penlu (Dec 9, 2010)

You mean like CLR? Wonder what that would do to the plastic. I remember using rubbing alcohol or nail polish remover.


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## penlu (Dec 9, 2010)

PS, one hint I like a lot is tacking the track down temporarily with thumbtacks. Holds the joints together firmly but much easier to pick up without destroying track than track nails. 

This is a great site! http://www.building-your-model-railroad.com/


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## novice (Feb 2, 2011)

Not CLR, I bought this stuff called Loctite naval Jelly rust desolver.

Thanks for the link - I think I have that one bookmarked, along with dozens of others I found. If you want some links, let me know - I'm a link-a-holic 

I haven't gotten to laying track permanent yet. I hope to be building my benches this weekend.

Still up in the air about the foundation and what I want to use for the track. I'm torn because I want to make the whole thing modular/sectional to be able to break it down and move it later so I don't have to go through this again.


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## gunrunnerjohn (Nov 10, 2010)

penlu said:


> I understand about not using steel wool... little shreds get sucked up into the engines and ruin the motors. But why not sandpaper? (I've used emery cloth)


It also takes any remaining plating off.


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## NIMT (Jan 6, 2011)

Most of us don't use nails at all anymore. It's easier and quicker to put the base (cork or foam rubber) and track down with clear latex caulk.
Stays put , expands and contracts with hot and cold, and is super easy to remove if you need to relocate a track.


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## novice (Feb 2, 2011)

Thanks Sean - I read that I think in one of your other threads. That's probably how I'm gonna go also.

I have it pinned down at the moment while I finalize the layout.


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## Reckers (Oct 11, 2009)

Gunrunnerrjohn makes an excellent point: if you're running a nickel-silver plated track and you sand off the nickel-silver, you've defeated the purpose of getting nice track.

Aside from that, you have to understand the mechanics of crud acquisition. If you put two wires on your transformer and touch them together, you get a spark and you get a carbon deposit---a little black, sooty spot. On the other hand, if you put an alligator clip on the end of each wire, upend your locomotive and clip the wires to the pickups before turning on the tranny, the wheels spin but you get no spark: why is that? It's because you have constant contact between your power source and your motor. Now, let's return to the track.

If your wheels are clean and polished, and your track is glassy-smooth and clean, you have an area of perfect contact between your wheels and your track: let's call it 2 milimeters, from front to back, for discussion. As the train rolls forward, the trailing edge loses contact with the track, the center of your 2 mm expanse maintians brief contact, and a new area of contact is created at the front of each wheel as it turns and touches the track. You maintain a state of perfect contact, and create no spark by breaking and reconnecting your circuit momentarily.

Now, let's sand that track! We not only remove all that surface crud---dirt and oil baked onto the track by the heat of the spark that fried it----but also introduce a zillion little scrapes and gouges into the surface of the track as the sandpaper does what sandpaper does. We now have a corrugated track surface, with all those micro-scratches cut into the rails. As your beautifully-polished wheels roll across them, the electrical contact begins breaking and reconnecting, over and over and over and over and over.....and each time, creates a carbon deposit that does not conduct electricity. It also sears any grease, oil, or dirt onto your track surface. You now have track that has a coating that protects it from the elements and, unfortunately, is non-conductive. Your trains no longer run on it.
There is no religious argument against the use of sandpaper, grinders, wire wheels and so on: there is a time and place for every tool and resource. Logically, though, those are tools of last resort because of the consequences of their use. Sandpaper giveth, and sandpaper taketh away: you use it to remove heavy rust and crud and then you have to find a way to remove the effects of the sandpaper. Replating your track is generally not an option, so our rule of thumb is "no sandpaper" for track cleaning.

Now, before I put the soapbox away, no steel wool because it breaks into lots of fragments you can't see. However, the magnetic field in your engine can find them just find, invites them in and they're all over your magnets, armatures, gears and any oily or greasy surface like 14-year-olds on your living-room furniture. Like 14-year-olds, they will also eat up anything you offer, such as bearing surfaces in your motors, the places where your axles rotate, and so on. That's why the other rule of thumb is "no steel wool".

Enjoy your weekend!


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## gunrunnerjohn (Nov 10, 2010)

Just imagine steel wool and my magnatraction engines!


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