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Atlas U30C Silver amperage

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  • Member since
    November, 2015
  • 19 posts
Atlas U30C Silver amperage
Posted by ROCK MILW on Monday, January 08, 2018 10:16 AM

I recently purchased a pair of new Atlas U30C Silver locomotives at a train show.  The locomotives are operated as DC units on my DC-powered layout (they have no decoders or speakers installed.)  Unlike my other locomotives, these two U30Cs draw a very high amperage: each one draws 1 to 1.5 amps, depending on train length, grade, etc.  Both headlights operate no matter what direction the locomotive is moving.

I removed the shell from one of them and operated it for a short time, looking for a short or anything unusual.  When I touched the PC board I nearly burned my finger from the heat being generated.  That was quite a surprise.  I am guessing that the PC board is not intended to handle 1 to 1.5 amps, and that is why it is so hot to the touch.

These locomotives are rather heavy and are both good pullers, but I cannot understand why their amperage draw is so much greater than my other locomotives, including some of my old Blue Box Athearns.  Perhaps the motors are on their last legs?  Or the PC boards are flawed?  Any ideas would be appreciated.  Thanks.

Tags: Amperage , Atlas
  • Member since
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Posted by mbinsewi on Monday, January 08, 2018 10:50 AM

Or, maybe something is binding, or causing a resistance, like maybe old grease in the trucks and gears?

Do you have to keep turning up the throttle on your DC power pack to get them to move?

Just throwing some ideas out there!

Mike.

  • Member since
    January, 2009
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Posted by RR_Mel on Monday, January 08, 2018 11:10 AM

Are they new or used?  If they are used locomotives check the entire locomotive for modifications from the previous owner.  I haven’t seen the foil on a circuit get warm before.  I agree over one amp is way too much for a modern locomotive.
 
Are there resistors on the board?  They could be in series with the bulbs and under sized in wattage.  If the bulbs are incandescent you could use a diode in series to make them directional.  If they are LEDs and operate in both directions they are most likely driven from a bridge diode and can be rewired to be directional.
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
  
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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  • From: Ontario Canada
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Posted by Mark R. on Monday, January 08, 2018 10:46 PM

I have quite a few of those on my roster and when running with a train pull 200 to 250 ma. Something is definitely amiss. 

Try disconnecting the truck wires and motor wires from the board and connect the trucks directly to the motor (bypassing the board) and re-test your current draw.

If it's still high, there are probably some bad windings in the motor and should be replaced. If it's down to where it should be for current draw, the problem is the circuit board. Either get a replacement board, or make something of your own design - there's not much to it.

Mark.

¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ

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Posted by SouthPenn on Tuesday, January 09, 2018 8:17 AM

Sounds like there is something rubbing on the drive shafts or flywheels. Or the drive wheels have something binding them. 

South Penn
  • Member since
    November, 2015
  • 19 posts
Posted by ROCK MILW on Tuesday, January 09, 2018 8:41 AM

Thanks for all of your input, everyone.  I'm in the midst of signal system wiring, but as soon as I get tired of that I will start some U30C "surgery" using your ideas.

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