I'm with Bob about the new & old transformers, don't phase them, the sign wave output may not be the same. Use two older transformers together or two new transformers.
Also I would not try to phase a CW-80 with anything but another CW-80 of the same series.
Thanks, Bob. I work with the group of six or so guys who assemble and operate the holiday toy train layouts for visitors to the Museum of Transportation in St. Louis. The two O Gauge loops on the main layout are powered by a Z-4000. We power the various switch machines from the 14 v. fixed post on the Z-4000 with the outer rails providing the return. Miscellaneous accessories such as gates, flashers, gatemen, beacons and lights are powered by whatever old Lionel or AF transformers we find. I didn't know if I could save wire by phasing the old and new transformers and using the rails for the return for those accessories.
It is true that voltage sources can be connected to a common return in such a way that those outputs are in phase. But that does not mean that the voltage waveforms match. When both have the same frequency and waveshape, and are adjusted to the same amplitude, a match is possible. But your intuition that a transformer with a sinusoidal waveshape and one with a phase-controlled (not "chopped") waveshape cannot be matched is correct--they cannot.
Nevertheless, it is good to have track voltages in phase with each other, to reduce the fault current that will flow when a train accidentally crosses between blocks powered by different sources. You should not do this deliberately, although many operators do, not realizing, or not believing, that there is any risk in doing so.
There is no reason why accessories must be fed from voltages that are in phase, either with each other or with the track. Even a turnout with a non-derailing feature like an 022 or a crossing gate like a 252 that is activated by a control rail can be powered from a source that is out of phase with the track voltage. In fact, the voltage source can have not only a different phase, but a different waveform and amplitude and even a different frequency. For example, I power all my (O27) turnouts with DC voltage (zero hertz) through resistor-capacitor networks, to prevent coil burnouts.
Powering accessories that are returned through the track or through a common bus that is shared with the track even has the advantage that the return currents from the train and accessories partially cancel each other, reducing rather than increasing voltage drop in the bus. This is the same principle that the three-wire 120/240-volt split-phase electrical service exploits.
Bob Nelson
OK, thanks!
But it works for Marty, and it works for me(and many others).
I have phased, all on the same layout, to each other in several combinations, a ZW(250)(sine wave) with two PM-1s(chopped wave), PH-1(sine wave), RS-1(chopped wave), CW-80(chopped wave), KW(sine wave), MW(chopped wave),and PowerChief 120(chopped wave).
Rob
No.
OK, thanks. You're guaranteeing to me that the sine wave of the old transformer and the modified wave of the new transformer will not interfere in any way or cause damage?
Link fixed.
The link you posted appears to be on different subject matter.
Don't assume anything. What you propose is done all the time. Here is a terrific tutorial to do exactly what you want(ZW-C Controller substituted for the Z-4000):
Marty E Tips, Tricks
I am familiar with phasing conventional old transformers, so that each can contribute various voltages to use for different accessories in a common-ground set-up using a bus bar or the outer rails for a common ground. Am I correct in assuming, however, that you cannot phase a conventional transformer with something like an MTH Z-4000, due to the different electrical characteristics of the modern transformers?
Our community is FREE to join. To participate you must either login or register for an account.
Get the Classic Toy Trains newsletter delivered to your inbox twice a month