Original Lionel ZW-real rating?

Hudson 5432,

   Got to tell you that I only knew of two different ZW's the Pre War 250 and the post War 275, and they both run my trains without any trouble, including DCS.

Maybe one of these Electric engineers will explain this to both of us.

PCRR/Dave

The post war 275 ZW  No R on this ZW

The Pre War 250 ZW  No R on this ZW

Previous post that may be helpful.

https://ogrforum.com/d...3083/reply/lastReply

If memory serves, I've read a number of times that the "continuous" rating is 180 W.

I have always felt that the maximum output of a pw ZW was in the 170-180 watt range as its efficiency dropped when hot from continous running but it is difficult to pin it down.

During the early-mid 1990s I was operating 3 pw 275 ZWs to supply trains on five 14x32 tracks, ovals that were basic run and display. After 1-2 hours when they were warm to hot the efficiency definitely dropped. I was on sometimes iffy TVA power so I always kept a check on the service voltage that at times in summer dropped to 108-110 VAC. Normally it registered 120VAC.

I only had a wattage meter check once by a Mountain Electric Rep and fellow O-gauger nearing the end of a 3 hour running stint and it read 178 watts. The Fluke clamp on ammeter reading on A&B combined was just under 9 amps. The load: with the "A" throttle wide open on my 30 hopper coal train behind a Challenger and a 14 car[11 lighted] passenger car train behind 4-motored Weaver E8s on track #2 with throttle "B" wide open. I had often blown external connected cartridge fuses in the 2-3 hour running period absent finding a short of any type so rightly or wrong I had concluded that it began to overload max capacity as the efficiency dropped...

A Engineer and O-gauger from the Ordnance Plant in East Tennessee claimed similar results but I don't know his protocol.
My guess is that for short term efficient running the total net output is probably around 200 watts or 10+ amps.

ZW Output Test

Rob,

   Thanks much for the education, this is exactly what I wanted to know.  It's no surprise both my ZW's act almost identically on my layout.  In reality once I set the voltage for the DCS both the ZW's preform just fine.

PCRR/Dave

Our museum has a two-loop Marx layout that runs for four hours straight on open house days, powered by a ZW. Our postwar wizard cut a hole in the case and rigged up a computer fan to cool it. Works great. 

I agree that 170 watts or so is about max continuous load on a ZW; and even then it will get very hot. The problem is that the case is enclosed, and there is no cooling.

I tested a Z-4000 a couple of years ago at a continuous 400 watt load and the air at the outlet was about 25-30 degrees warmer than the room temp.

It worked just great. The input was right around 550 watts all the while.

Rod

Thanks. Just what I wanted to know.