# Education on amps, voltage, etc.



## tcaron20 (Nov 19, 2010)

I'm running a pretty simple one train setup with a MRC 6200 power/controller. I'm learnig that a "center off" LGB controller might make it easier to control my new LGB reverse loop.

Is LGB the only one that makes a "center-off" controller?

Also with my setup would a higher amperage be of a benefit? Does higher amperage make the train run faster or stronger?

What are the limitations of 1 amp vs 5 amp? 

What does higher VA output do?

Thanks!

Tom C


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## lownote (Jan 3, 2008)

Higher voltage will make them run faster. Higher amperage will allow them to draw more current.

If you think of electricity as water in a pipe, you might think of voltage as the speed the water is traveling, and amperage as the size of the pipe. 


Imagine the water in the pipe is turning a wheel. A narrow pipe, and fast moving water (voltage), will get that thing wheel moving pretty fast. But hold your hand to the wheel, and you can easily stop it. 


Now triple the size of the pipe (amperage), with the same water speed--the wheel will be much much harder to stop or slow 



Think of it this way-- your transformer puts out, let's say, 16 volts at 1.5 amps. You put a loco on the track and it runs nicely. If you add a really long train of cars, it takes more power to move at the same speed. A low amperage transformer will cut out and trip its internal breakers. A high amperage transformer will keep going. Also if you may have noticed that if you put more than one loco on the track, they both slow down, and eventually the circuit breaker trips--that's an effect of low amperage.


Long trains, big multiple motor heavy engines, lots of lights, smoke and sound, steep grades--all these things require more amperage. short trains, small engines, level ground, no "bells and whistles" requires less amperage


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## Greg Elmassian (Jan 3, 2008)

A note on "VA", Volt-Amps.... 

This is normally a poor way to express the power capacity of a power supply. 

It is indeed "volts" times "amps" BUT only at some combination of voltage and amps, NOT at EVERY combination... 

I'll use the MRC 6200 as an example: from their specs: "Mode I: 0-18.5 Volts DC, 35 VA Max, 18 Volts AC; Total: 60VA" 

The first thing people "miss" is that the 60VA rating is NOT for the track output, it's the total of the track output and the accessory output... 

So, the track output is 35 va... 

So it can put out a max of 18.5 volts. 

And it can put out 35 va "max", which makes many people think, well 35 / 18.5, I should get 1.9 amps, right at 18.5 volts 

WRONG 

All VA means is that there is SOME combination of output voltage times output current that gives you 35. 

The reality is that the output voltage sags terribly near 2 amps output, and this unit can barely run one loco in many cases. 

Quality products will state that they are X amps and X volts max. 

Rule of thumb, when you see VA, you should look for another unit unless you are only running one loco, short trains, and no grades... Many G scale locos will draw 2 amps under heavy loads. 

Regards, Greg


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## Tom Parkins (Jan 2, 2008)

I can't help with LGB power packs, but I can help with volts and amps since I do this for a living. 

Electricity is the flow of electrons. Everything done in electricity is done with electrons or the absence of electrons. Amps is a measure of the number of electrons passing by a point every second. Voltage is a measure of the "pressure" pushing these electrons down the wire. 

On cheaper powerpacks you are limited to the number of electrons you can deliver to the motors and lights etc. Limited to 1-2 amps. Unless it is a regulated powerpack, the voltage will often fall off as the amps increase. So if you put out 1 amp at 15 volts (VA = volts x amps) = 15VA (watts). Increase the load, go up a hill, turn on the smoke, and more amps are needed but the ability to push them down the wire is decreased. So now you have 1.5 amps but only 10 volts. VA sill= 15. 

On bigger power supplies, they have the ability to push out more amps and also maintain the volts. That's why when you go up grade with a big power supply you do not lose speed. It's the amps that go up and down as the load changes. Voltage should remain constant. 


Much easier to diagram on a white board and sit at a bench and show you meters, but I hope this short explanation helps. Recommendation for newbies is to by a quality power supply with plenty of power. Don't scrimp on power. 


Tom P


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## tcaron20 (Nov 19, 2010)

Thanks everyone for the info. Just what I was looking for.

Now it is clear that I need a higher amperage power/controller with a higher VA rating, less the accessories draw.

Any recommendations to be able to power at least one, all I'll be running at one time, locomotive with a respectable rolling stock say 5 to 6 cars?

Look like my MRC 6200 while a well built power supply/controller, may be a bit underpowered for grades, etc.

Thanks,

Tom C


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## tcaron20 (Nov 19, 2010)

I got an Accucraft Lilly Belle electric that seems to run a bit slow. It weights in at about 13 lbs. Could my MRC 6200 be underpowered, which would explain the slow running? 

Tom C


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## rhyman (Apr 19, 2009)

As an "Okie", I feel obligated to share a few power supply ideas with the rest of the group. First of all, you need to understand volts, amps and power. Here are a few tips when working with power supplies:

There is always room for improvement. I'm working on some new experiments with chemicals, electricity and power supplies. Still haven't finished checking out which combination of electricity and water works best on Mondays. I can't seem to get past 3 quarts of water per 220 volts of electricity. The lights don't stay on long enough to read the gauges. Maybe higher amperage will work better ... yeah ... that's it ... higher amperage ... that sounds like the right solution. Note to family: Expect power outage throughout the Oklahoma City metro area at 1:45 PM Monday.

I'm also busy testing the latest power supplies. Do you realize what improvements you can get out of a Bachmann “Big Hauler” power supply when you wire it with three phase 480 volts? 

Famous Okie saying: "Hey y'all, watch this! ... YAHOOOO !!!" Uh oh ... there goes my neighbor playing with his 911 speed dial thingy again.

Fear your wife when she catches you modifying power supplies. I speak from experience. But don't be intimidated by what your wife says is inappropriate use of electricity. Remember ... she's not always around to watch you.

You want real intimidation? Just spend an afternoon running on my layout with my experimental power supplies. It might be a good idea to leave before the explosion though, unless you're wearing asbestos underwear. As we say in Oklahoma, "Blow it up, but blow it up wisely." I usually prefer fissionable materials but I'll try anything once. At last count the State had imposed a surcharge on any power supply shipped into the county where I live. This is to offset the additional fire and paramedic protection that is required for anyone within a fifty-mile radius. "Hello? ... 911? ... Yep, it's me again."

Most of you are far enough away to avoid the fallout. But only because of these gol dang new wimpy power supplies ... they don't give as big a bang as the old gas guzzlers that made modeling more dramatic. I sure get nostalgic thinking about the good ol' days when power supplies were included in the Nuclear Arms Treaties. Back then, the only thing to fear was fear itself ... and maybe the mushroom shaped cloud over the layout.

That reminds me, I probably should warn you about using denatured alcohol and shoe dye to stain your wooden ties. Go very easy on the alcohol until you get used to mixing it. When in doubt, it's better to use less. That is, unless you want to try ... nah, just use less. I would send pictures, but the insurance investigators are holding those until they determine the cause of the ... aw, you know.

A good homeowners insurance policy is highly recommended when modifying power supplies. Put 911 on speed dial. Get to know your local SWAT Team. Trust me ... I know of what I speak.


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## Greg Elmassian (Jan 3, 2008)

My stock recommendation on a power supply for DC is the MRC power G, 10 amps, and up to 24 volts. Runs anything. Nice big handle, heavy duty toggle switch.

Many people on the forum have bought them and like them.

*http://www.modelrec.com/search/product-view.asp?ID=1266*

(Don't freak out on the price, that is list, no one buys them at list)










Regards, Greg


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## BaileyWood (Dec 15, 2010)

Several questions in the same vein:

1. What is the voltage output of the accessory ports on the back wall of the LGB Krauss Locomotive?
2. Is it dependent on how much the transformer is putting out? 

I am trying to wire up some LED X-mas lights to my LGB locomotive (they run on '2' 1.5volt C-cell batteries) and wanted to see if it is possible to connect them to the accessory plug/port.

Thanks for having a beginners forum . . . 

B


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## Greg Elmassian (Jan 3, 2008)

Welcome to the forum. 

A piece of advice: you have a specific question on a specific loco... 

You need to start a thread with that information in the subject. 

"adding on" to an existing thread called "Education on amps, voltage, etc." will not get you the "audience" for your problem. Do NOT be afraid to start a new thread with just your question! 

also, by somewhat "derailing" the thread's subject, then in the future, searching for information is made harder, since no one would think to find information about a LGB Krauss loco in a "general education" thread. 

Again, welcome, and do not feel inhibited to make a new thread for a new topic, that's why it's easy to do! 

Regards, Greg


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