Here's a handy chart that a friend sent me he created from the specifications of various post-war transformers, Interesting information, I figured it was worth sharing. It's somewhat illuminating.
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Thanks @gunrunnerjohn ! I’ve always heard the ZW 250 was more “powerful” than the 275. I guess this chart shows that while the ZW 275 has the higher total output, the ZW 250 makes a slightly more efficient usage of its output.
Keep in mind, these comments are only in regards to how may outputs are being used:
I love the type Z and type V transformers. If refurbished and with a fast-acting breaker(when used for track power via conventional or command) they’re great- and, as most know, are great for powering accessories. IMO, hard to beat the type V and Z when it comes to powering lighted or operating accessories.
I really like the tidbits regarding the KW, SW, LW, and TW. I know the LW has long been heralded as the postwar era’s “most powerful” transformer in terms of track output- which this chart confirms(if the KW & SW centertap info is true). Further, the LW & TW’s fixed 18v output is very useful.
this chart is definitely very helpful for anyone using Postwar transformers, in general, but to me especially for command. While I use bricks for all my Command track power, if I had to resort to my ZW 250, Z or V-this chart does a good job offering a the numbers to input in the method to figure if you’ll get the 18v necessary when the train is running underload.
For beginners, start with figuring how much your modern loco power w/ can motors draws with an unlit consist- then work your way up by adding lighted cars. If your using the above transformers to power Postwar locos but running via DCS, Legacy it TMCC- check the Postwar instruction manuals that Lionel included in their sets. These manuals Break down how many watts are drawn by the AC open-frame(pulmor) motors and dileneate between O-27 & O engines w/ or w/o smoke and/or whistle, the wattage of a 167 whistle controller)m(for conventional) and the wattage drawn by a bulb with “x” voltage. Each loco’s wattage rating is given a range which I believe is to account for whether it’s a single or double motored engine. Ex- it shows an O-27 loco draws 15-25 Watts(not including whistle or smoke). let’s combine that with the above chart. Let’s say I’m running my B&O Buds RDC 400, by itself, w/ whistle & 2 large 12 volt bulbs. My Buds RDC is drawing about 41 Watts(for simplicity let’s say 40).If I’m using my grandfather’s 1033 and I’m applying 10 volts to the track to start- my Buds is requiring 40 watts at 4 amps. Thus, my 1033 is fine for that Buds but if I add two non-powered Budds with 2 large 12v bulbs each, And a single Prewar 18 volt lamp post- I’m darn near my max. See page 44 in this link:
https://ogrforum.com/...83860657/Booklet.pdf
Again, thanks to grj for posting this!
@StevefromPA posted:I really like the tidbits regarding the KW, SW, LW, and TW. I know the LW has long been heralded as the postwar era’s “most powerful” transformer in terms of track output- which this chart confirms(if the KW & SW centertap info is true). Further, the LW & TW’s fixed 18v output is very useful.
I can't put too much faith in these findings as it's very obvious the author knows very little about the architecture of so many of these transformers. The KW & SW for example both use one secondary tap and the entire output(aside from the compensating winding) is available from any one handle.
The entire output is also available, 6-7 amps, from the throttle on the LW w/o accessories connected. The load is shared among all outputs and approaches 6-7 amps.
The chart also leaves out the effect of heat on a fully warmed up transformer, which would be much more telling of the efficiency of a given design.
The 20 volt fixed voltage of the KW is actually ideal for powering the PM-1 for conventional or command use, the voltage drops off quickly once a load is put on it but it holds in the 17-18 volt range very well.
Here is some empirical data with findings that come across much more credible on the ZW 250 vs 275 performance.
Interesting point Rob, he stated it was from "specifications". I'll see if I can get more details on where the numbers where sourced.
