been quite sometime and Im dabbing around with the idea of useing one ho scale decoder to control 2 N scale of the same loco leashed together (wired), permant lashe up , for a project . I relize both units would need to have Idenical running character AND the AMP rateing of decoder would need to be over that of 2 N scale motors . that said would 2 motors wreek havick on the decoder say EMF and such ? thanks in advance...Jerr
Jerr,
I would guess not because of the good possibility of both motors exceeeding the decoder's maximum current draw while pulling a load. Better to use two identical decoders - one for each locomotive - and MU them together. The other option would be to remove or disconnect (mechanically and electrically) the motor from the 2nd unit and run the lash-up with only one motor.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
BEMF, the voltage generated by the motor due to it spinning in a magnetic field reduces the voltage across the windings. If one motor were turning faster than the other, the slower one would draw more current. Seems to me that, assuming they have the same characteristics, that they would have to turn at the same speed. This could be a problem if there was more friction in one motor than the other.
greg - Philadelphia & Reading / Reading
BIG JERR been quite sometime and Im dabbing around with the idea of useing one ho scale decoder to control 2 N scale of the same loco leashed together (wired), permant lashe up , for a project . I relize both units would need to have Idenical running character AND the AMP rateing of decoder would need to be over that of 2 N scale motors . that said would 2 motors wreek havick on the decoder say EMF and such ? thanks in advance...Jerr
Rich
Alton Junction
BEMF is used by the decoder to better control motor speed. If a decoder ran two motors, it couldn't sort out which motor was giving it a particular input, nor could it "tell" each motor individually how to compensate.
And, as far as I can see, the BEMF feature is a really good thing and not to be switched off. Which I believe you would have to do to run two motors from one decoder.
To be clear, you CAN have two decoders with the same address. If you want. For example, I've got a cow-calf switcher set that I will be DCC-ing. Two decoders. Both will be 2400. I am assuming I have to program each decoder separately. No big deal, really.
Ed
Two motors powered by one decoder will work just fine as long as they don't exceed the power capacity of the decoder (not likely with modern N-scale motors). Bemf compensation will just see the average of the two motors. As an example, the Bachmann DD40AX has two motors and I have one running with a DZ125 with bemf compensation enabled and it runs fine.
sounds fair , I think I shall give it a go , I can always add another decoder if problems , thanks Jerr
Yes you can most likely use one decoder for two engines, but you lose one of the great advantages of DCC - speed matching. With separate decoders, you can adjust the speed and momentum of the two engines so they run perfectly together like one unit.
I have several sets of engines that only run with each other - like two switchers that always run together back to back, or an A-B set of F units. I just gave each one the same ID number, and just treat them like one unit.
BIG JERRbeen quite sometime and Im dabbing around with the idea of useing one ho scale decoder to control 2 N scale of the same loco leashed together (wired), permant lashe up , for a project
What is the benefit that you perceive from doing this? You'll lose speed adjustment and independent control of the lights. And just lifting the two units on- and off the layout will be trickier.
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Some years ago I bouth a PCM F3, HO scale with decoder, motor and speaker in the A unit and motor and speaker in the B unit. A and B units close coupled with a six pin connector hidden by the diaphrams.
Runs quite well.
Sometime later bought a BLI F7, DC only. Installed LED's, Tsunami in each unit with speaker in each unit. Ran them a few times in ABBA. They could pull.
Connecting your A and B will be the main issue.
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
richg1998Connecting your A and B will be the main issue.
I don't think that the Original Poster said that what he had were A- and B-units. If they are, then drawbars make more sense.
I assumed two A units back to back. Two wires for pickups in second unit, might not be needed. Two for motor and two for lights.
Sounds like a permanet drawbar. Wire could be #30 magnet wire or a little smaller painted black. Smaller diameter than rubber covered #30 decoder wire. I have used #30 magnet wire. Just leave it on the layout.
Seriously doubt two N scale would exceed any one amp decoder.
I used my setup as examples. The B unit could just be the rear of an A unit.
A worthy experiment. Part of model railroading.
We used to do this years ago when basic N scale decoders cost upwards of $40 each. (2 digit, two function decoders) It worked but quickly became a real PITA when service was required. Even wheel cleaning was a burden. As previously mentioned, speed matching was not possible so the engines needed to be as close to the same as possible. Once decoders got cheaper and smaller, two-on-one installations became a thing of the past.
Martin Myers
richg1998I assumed two A units back to back.
Maybe, he didn't say.
richg1998A worthy experiment. Part of model railroading.
Personally, I'd just use two decoders and save my experimenting for something truly new. But to each his or her own.
mfm37It worked but quickly became a real PITA when service was required. Even wheel cleaning was a burden.
+1