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NOT choosing between DCC and DC...

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  • Member since
    February 2007
  • From: Holland Michigan
  • 108 posts
Posted by onebiglizard on Thursday, December 6, 2007 10:49 AM

Like many, I have a fleet of DC locos and am planning (soon I hope) to convert my layout to DCC.  I have always assumed that I could convert these old DC units at my leisure, while continuing to use them on the DCC layout with address "0".

However, the posts here indicating the problems with a DC unit on a full voltage DCC track opened my eyes - I can see where you could easily smoke a motor.

It seems like I'm missing something though.  Most (or all?) of the DCC suppliers indicate you can run a single DC unit on a DCC layout.  Sounds from the posts that that may be true, with some risk to your DC motor.  But does that only work if you operate your DC loco in a block that is electrically isolated from the sections running DCC?  Are the 1-DC-unit-on-your-DCC-layout assurances from the manufacturers misleading, or am I just dense?

 Thanks,

Bill Field    

 

  • Member since
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  • From: New Brighton, MN
  • 4,393 posts
Posted by ARTHILL on Thursday, December 6, 2007 11:00 AM

I have had no problems with my DC engines. Maybe later.

You do not have to run them on an isolated block. You store them on an isolated block. You run them of the DCC track like any other engine. Though you can only run one DC engine at a time, you can run them with as many DCC engines as you have throttles for.

If you think you have it right, your standards are too low. my photos http://s12.photobucket.com/albums/a235/ARTHILL/ Art
  • Member since
    July 2006
  • From: Vail, AZ
  • 1,943 posts
Posted by Vail and Southwestern RR on Thursday, December 6, 2007 11:11 AM
 onebiglizard wrote:

Like many, I have a fleet of DC locos and am planning (soon I hope) to convert my layout to DCC.  I have always assumed that I could convert these old DC units at my leisure, while continuing to use them on the DCC layout with address "0".

However, the posts here indicating the problems with a DC unit on a full voltage DCC track opened my eyes - I can see where you could easily smoke a motor.

It seems like I'm missing something though.  Most (or all?) of the DCC suppliers indicate you can run a single DC unit on a DCC layout.  Sounds from the posts that that may be true, with some risk to your DC motor.  But does that only work if you operate your DC loco in a block that is electrically isolated from the sections running DCC?  Are the 1-DC-unit-on-your-DCC-layout assurances from the manufacturers misleading, or am I just dense?

 Thanks,

Bill Field    

 

I think at this point you would only say that 'some' DCC systems support running one DC loco.  There are a few reasons, the first being that running the DC loco reduces the performance of the DCC system.  It isn't a huge problem, but the more trains there are running, the bigger the problem is.  I think that another reason is that decoders have gotten smaller and cheaper, generally, so there are few reasons not to convert (thought there are certainly still reasons).  Another reason is that to many people (and I'd say I'm in this camp) the noise when running a DC loco can be almost unbearable.  One other reason (and I won't say last, since there are proabably more) is that SOME motors don't like running in this mode and do burn out. 

The DC loco operated on the same track as the DCC locos.  The mode of operation is sort of pulse control taken to an extreme.  The voltage is flipping between full forward and full reverse, with the direction you want to go getting longer pulses.  Some engines perform better in this mode than others.

Jeff But it's a dry heat!

  • Member since
    September 2007
  • From: Charlotte, NC
  • 6,099 posts
Posted by Phoebe Vet on Thursday, December 6, 2007 1:48 PM
 onebiglizard wrote:

Like many, I have a fleet of DC locos and am planning (soon I hope) to convert my layout to DCC.  I have always assumed that I could convert these old DC units at my leisure, while continuing to use them on the DCC layout with address "0".

However, the posts here indicating the problems with a DC unit on a full voltage DCC track opened my eyes - I can see where you could easily smoke a motor.

It seems like I'm missing something though.  Most (or all?) of the DCC suppliers indicate you can run a single DC unit on a DCC layout.  Sounds from the posts that that may be true, with some risk to your DC motor.  But does that only work if you operate your DC loco in a block that is electrically isolated from the sections running DCC?  Are the 1-DC-unit-on-your-DCC-layout assurances from the manufacturers misleading, or am I just dense?

 Thanks,

Bill Field    

 

The AC voltage on the track does send reversing voltage to your DC engine.  The control of it on address zero comes from stretching the zero pulse on one side or the other.  That is not as efficient as DC, so the train will not perform as well, but it does not hurt your engine.  The cooling of your electric motor in the engine comes from the spinning armature.  The danger to your DC engine occurrs when it is not moving.  It is getting the rapidly reversing current, but no armature movement, so it overheats.  The overheat CAN (not necessarly will) burn out the motor.  No separate blocks are required to mix DC & DCC, but you should remove your DC engines from powered track if they are not moving.  Since DC engines cannot read the digital pulses, if you have more than one DC engine on the track at the same time, all DC engines will respond to the zero address just like they would if they were all in the same block of a DC layout.

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
    December 2004
  • From: Pa.
  • 3,361 posts
Posted by DigitalGriffin on Thursday, December 6, 2007 5:01 PM
 Phoebe Vet wrote:

The AC voltage on the track does send reversing voltage to your DC engine.  The control of it on address zero comes from stretching the zero pulse on one side or the other.  That is not as efficient as DC, so the train will not perform as well, but it does not hurt your engine.  The cooling of your electric motor in the engine comes from the spinning armature.  The danger to your DC engine occurrs when it is not moving.  It is getting the rapidly reversing current, but no armature movement, so it overheats.  The overheat CAN (not necessarly will) burn out the motor.  No separate blocks are required to mix DC & DCC, but you should remove your DC engines from powered track if they are not moving.  Since DC engines cannot read the digital pulses, if you have more than one DC engine on the track at the same time, all DC engines will respond to the zero address just like they would if they were all in the same block of a DC layout.

Very well explained!  When the DC train is not moving KILL the power!  (Sorry Art, I didn't mean to sound like I was picking on you.  I'm just throwing out a warning to others contemplating this.)

I will throw in two more cents and state that pancake motors (Tyco) and open frame motors don't do as well as can type motors.

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

  • Member since
    July 2003
  • From: Appleton, WI
  • 275 posts
Posted by tormadel on Thursday, December 6, 2007 7:51 PM

On another note along this line. I'm also assuming it would be the course of wisdom to finish collecting my pieces and get started on building the layout first. Because of changing technologies the more you wait the most latest bells and whistles you'll get for your buck.

  • Member since
    July 2006
  • 177 posts
Posted by corksean12 on Friday, December 7, 2007 3:17 PM
Thanks everyone, I didnt know n and z scale decoders could be used in HO scale (technically I am modelling OO but its not much of difference and its quicker to say HO), i will have to check that out. I think I will still go the jack and plugs route though, so i can get an automatic shuttle  system.
Modelling a short GWR branch line that runs from West England to a small Welsh community
  • Member since
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  • From: Mpls/St.Paul
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Posted by wjstix on Friday, December 7, 2007 3:52 PM

 corksean12 wrote:
Thanks everyone, I didnt know n and z scale decoders could be used in HO scale (technically I am modelling OO but its not much of difference and its quicker to say HO), i will have to check that out. I think I will still go the jack and plugs route though, so i can get an automatic shuttle  system.

Now that I think about it, I believe I have an old Walthers FM H-10-44 switcher that has a Digitrax Z decoder in it.

BTW about decoders flopping around - it's a mixed thing, you want the decoder to stay in place but you have to be careful as decoders can get hot, and will melt glue or even tape holding them in place. Usually I try to get the decoder somewhere where it's free from touching anything - like above a truck in a diesel - and then taping the wires leading up to the decoder in place. The wires coming from the decoder are stiff enough to hold it in place.

Stix
  • Member since
    July 2003
  • From: Appleton, WI
  • 275 posts
Posted by tormadel on Saturday, December 8, 2007 2:11 AM
Good tip, thanks.

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