# Transformers questions



## novice (Feb 2, 2011)

I have 5 transformers - If I'm not mistaken, I can't use the HO transformers with the O train - correct? 0 = AC, HO - DC or vice versa?

Is there a minimum and maximum power supply that should be used with either?

Does it depend on the number of accessories that are run?

Is there some kind of formula or guide to use when deciding on transformers?

Thanks in advance.


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## tjcruiser (Jan 10, 2010)

Most O trains are generally designed to run on AC power, though many motors will run on DC, too.

Most HO trains are generally designed to run on DC power ... you do NOT want to try to run them on AC ... if you do, you can easily burn out the "can style" motors.

This is not to be confused with DCC (digital) setups, which use a hybrid square-wave quasi AC power signal to send dedicated instructions to locos, accessories, etc.

Typical tranformer output is in the 16V to 24V range ... 18V to 22V being about the norm.


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## novice (Feb 2, 2011)

Thanks TJ what about wattage, does it matter?


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## gunrunnerjohn (Nov 10, 2010)

I caution you not to use DC with O-gauge stuff! Most of the electronic E-Units and electronic horns in conventional engines won't like it. TMCC/Legacy engines will certainly not work, and you can cook them with DC.


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## novice (Feb 2, 2011)

Thanks GRJ - from another thread, I know not to hook up the O to the DC transformer.

I wonder if that's why my engine is buzzing? LOL


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## gunrunnerjohn (Nov 10, 2010)

Actually, for conventional engines, the E-Unit can have a very loud buzz, the way they work. If you have three identical engines, the E-Units in each can make totally different sounds. 

There was a thread on running the E-Unit on DC to eliminate the buzz, it's a pretty simple modification. A bridge rectifier chip and a cap will totally silence the E-Unit.


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## novice (Feb 2, 2011)

Cool, I'll look for the thread - I thought this loco had a horn - all it does is Buzz when I press the horn button on the transformer.

Nothing but buzz, buzz buzz - everything is a buzz on this darn loco.


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## gunrunnerjohn (Nov 10, 2010)

Here's the thread we were talking about: http://www.modeltrainforum.com/showthread.php?t=6569&highlight=e-unit

I have little 1A bridge rectifiers I picked up from DigiKey, that and something like a 10uF electrolytic cap will quiet it right down.


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## jzrouterman (Nov 27, 2010)

novice said:


> Does it depend on the number of accessories that are run? Is there some kind of formula or guide to use when deciding on transformers? Thanks in advance.


With as many transformers that you have, accessories shouldn't be a problem. The only kind of formula that I can think of is what type of railroading are you planning to run. If you're wanting to run multi trains, independant of each other, then you have to use a seperate transformer for each train. Plus you'll also have to devide you layout into seperate electrical blocks. 

If you're wanting to run several powered engines together as one unit or several freights at the same time with just one transformer, then your transformer will have to be a model that is basically designed to handle this, like the MCR Power Command 9500 or the MRC Trainpower 6200 or one that can handle up to five engines at once without heating up to the touch. Most other transformers are not designed to handle these types of operations for any real length of time. An easy rule to remember when doing this type of an operation, is if your transformer heats up to the touch, then you need a bigger transformer. So, actually the only formula there is when purchasing a new transformer is basically "what do you want to do with it?" 

JZ


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## novice (Feb 2, 2011)

Here are the transformers I currently have:

80W Powerhouse - AC - O trains running on this now










Back of the powerhouse










The original transformer came with the Great Plains set:










DC- for HO










And another










I have another transformer that came with DeWitt set from Bachman, but it only has a direct wire plug - seems I can't use it for anything else but that set?


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## gunrunnerjohn (Nov 10, 2010)

Well, the first two are A/C transformers, the last two look like DC powerpacks for HO trains.


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## NIMT (Jan 6, 2011)

The first 2 AC units for the O's look fairly adequate to get the job done.:thumbsup:
The HO ones on the other hand are really weak and wimpy.:thumbsdown:
They are just the stock very low end models.
The main problem with these is there is little or no protection for overloads which in DC can be quite damaging! They have very little real power output. The controls are very rough and inconsistent.
As far as the DeWitt set goes probably the same problem. They all run in the same power so just cut the plug end off and wire it up.
They will work but if you want do do a huge upgrade for little $$ find a DC supply like this.:thumbsup: Your trains will love you for it!!
Dual cab runs to sections,blocks, or runs of track and it has overload protection. This is an older MRC model but it works well. The newer models are MRC Tech 4's I do believe.


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## jzrouterman (Nov 27, 2010)

NIMT.COM said:


> This is an older MRC model but it works well. The newer models are MRC Tech 4's I do believe.
> View attachment 8051


Here's a picture of that dual control Tech 4. 

http://web4.hobbylinc.com/gr/mrc/mrcab116.jpg

I have one of these. It's a pretty good little DC transformer for the money. It produces 16 va, though the throttles have to be turned a little over half way before the engines really begin to respond decently to it. It's not nearly as powerful as my larger transformers, but it's a keeper nonetheless. It can handle without any difficulty at least two, maybe three engines at a time on either throttle, though I don't really use it for that. That kind of work I leave to my other transformers to do. 

With this one though, I just use it to run a little SW1500 with one throttle and an RS36 with the other throttle doing switching operations in my yard, and servicing a couple of trackside businesses. I've run it like this several times for up to a couple of hours at a time and it has never gotten hot to the touch. If I had to rate it out of a possible ten, I'd give it an eight. 

Here's another Tech 4 DC transformer which is more powerful. It' a single throttle and it produces 20 va. It has a few extras features as well. Other than this, I really don't know that much about it, as I've never had this model. Here's a picture of it.

http://web4.hobbylinc.com/gr/mrc/mrcab131.jpg

Routerman


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