Decoder output question


lmackattack

lmackattack

old school
If I had powered A and B units that always ran with each other could I wire the decoder to power to the motors in both A and B units? or is this to much of a load to supply to both?

Trent
 
Sure, you can do that. You might want to be sure neither motor or drive train is binding, then make sure both motors are isolated from ground. It would only take two wires from Unit A to the the B unit to make this happen.
 
that was my idea Ken. 2 wires to the B unit with a plug incase I wanted to run just the A unit solo. This way I could install a sound/motor decoder in the A but have the B unit run with it as well. this would be with the same engine mfgs as speed steps would be fairly close to each other right out of the box. Im more concerned about smoking the decoder from that extra output needed.

Trent
 
Trent, at first thought you must be careful not to overload the decoder ampere rating. I would guess that 2 motors would push a 1 amp decoder to its limit, probably beyond depending on the load. If one or the other stalls, you will see smoke. ;)
 
Trent
True, you can do it, but why?:confused: Look at it from this angle. Sound decoder, 80 bucks or so. Plain decoder for B unit. 15 bucks. Having a short in either unit. Disasterous for the sound decoder since it is already working twice as hard as it would as a solo unit. Plus what if someday you want to run that B unit with a different engine? What if the A unit fails later down the road, now your B unit is as good as a paperweight!
IMHO it's just not worth the potential failure of a sound decoder. It's too easy with DCC to speed match units and make them all truly interchangable with each other. Give yourself the operational flexability of the prototype.
 
I agree 100% with Karl, especially when you're talking about a sound decoder. They are already working hard making sounds and you really don't want to add more load to them than a normal train will already do. A motor decoder for the B unit is cheap insurance for the sound decoder, in addition to the other advantages Karl mentioned.
 
DCCinstalled said it best,"It would be best to wire a decoder in each unit."

When you guys say you can do it are you saying it can be done safely and without damage to the single regular size decoder. I don't think so! You will start getting into the safety margin of the decoder by adding double the load it was designed for. Keep in mind that even though you may be within maximum spec. amperage you will still create a lot more heat and electronics hates heat. This is not a good idea and I would guess that is why the pro installers don't do it.

Now, you could get a large amp decoder and probably be alright and then we are back to what you are saying about WHY do this when a second cheapy decoder would do the work for a few bucks and no worries. Another thing to consider is the inherent differences in the two motors/gearing. How you going to adjust this out?
 
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Thanks for the advice. I dont have any A/B engines to wire up right now but was looking at a cow calf powered set up. I just wondered if it was something people do. I dident even think at about the issues of the cost to replace the sound decoder. I think I will just buy a $15 motor decoder in the B units and know that its safe.

thanks for the advice.

Trent
 
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