# How many amps do most LS trains draw?



## Ray Dunakin (Jan 6, 2008)

I have a friend who's interested in building his own control system. He wants to know how many amps a large scale train draws, just for the motors. (Not including lights, smoke, etc.)


----------



## chuck n (Jan 2, 2008)

I figure about 1 amp per motor. This is a little on the high side as most are between 0.5 and 1 amp per motor. 

Chuck


----------



## eheading (Jan 5, 2008)

My experience is exactly the same as yours, Chuck - between .5 and 1.0 amp/motor. I hadn't really thought of it on that basis until you posted your response, and I realized that is what I've seen on Aristo, USAT, and LGB locomotives that I have.

Ed


----------



## chuck n (Jan 2, 2008)

If he is going to pull long trains, have steep grades or sharp curves, you might want to use 2 amps per motor just to be on the safe side. All of those will make the motor work harder and pull more power. 1 amp is suitable for short trains on level track.


Chuck


----------



## armorsmith (Jun 1, 2008)

Ray, 

The best empirical data I can provide is based on my Bachmann K27 with original too high ratio drive. The conditions were: 

23 mixed consist of LGB, Bachmann and Aristo rolling stock 
Steel wheel sets with white lithium greased journals 
max 1.5% grade on the club mainline 

Running at 14.0 volts (eyeball proper scale speed) resulted in worst case of 1.1 amps on the grade. 

Hope this will help. 

Bob C.


----------



## Greg Elmassian (Jan 3, 2008)

When you design a system, you design for the average and the maximum. 

Average 1 to 1.5 I agree, maximum? I've seen way over this. Remember also that motors can draw high peak loads, and electronics have to handle this also. Under load, I have pulled 2.7 amps with both an Aristo Mallet, and various USAT locos. This was working them really hard, but not actual stall current, which can go even higher. 

Also, never forget the famous stall tests by George Schreyer (USAT GP7 I believe) where the amps briefly touched 14 if I remember correctly. 

So the system must be able to handle such extremes in one way or another. 

Regards, Greg


----------



## SD90WLMT (Feb 16, 2010)

I'll throw in my 2 cents here! 

I have a USA trains - SD70 Mac. I have read these motors are rated at 3.5 amps - per motor!! 

And, with an on-board amp meter wired in place, I have pulled 70 cars exceeding over 2.5 percent grades, running up to 7.0 amps and a bit more! Actual running conditions were about 6.3 to just over 7.0 - 7.1 amps. Yes, - it was very warm!, after running this heavy of a load, and has never been hurt doing so! 
I do run on the proverbial battery power also!! 

So I agree with Greg, - build, design and wire with fused protection for maximum loads, with-in the guidelines of the given equipment you will be running. And will you be running more than one loco ever? 

Dirk - DMS Ry.


----------



## Del Tapparo (Jan 4, 2008)

I would agree with the "most locos/trains are in the 0.5 to 1.0 amps range" for steady state running. All of my G-Scale Graphics motor controllers are designed to handle 5.0 amps continuous load, over the entire input voltage range of 7-30V. They will easily handle more during load spikes, although I don't have a spec for that. In extreme cases like hard working diesels, two controls could be consisted together, one for each motor. Although I do have many satisfied diesel customers apparently running fine on 5 amps or less. @import url(http://www.mylargescale.com/Providers/HtmlEditorProviders/CEHtmlEditorProvider/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/providers/htmleditorproviders/cehtmleditorprovider/dnngeneral.css);


----------

