# Post War ZW



## Patrick1544 (Apr 27, 2013)

Maybe this was asked before but I'll ask again. On a PW ZW, rated at 275watts, are all 4 taps 275 watts each or are they split at 68.75 each for a total 275?

This brings me to the next question. If they are 68.75 or 275, is there any reason to use a Power master which is rated at 135 or 180?

It seems like a power master wouldn't be enough, at 180watts to handle a 275watt ZW. 
Maybe I'm not understanding the concept of a Power master correctly.

Thanks


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## jesteck (Apr 15, 2014)

I don't know the particulars of the ZW other than it could run a couple of big honkin' trains and a lot of accessories back in the '50s, but output is output. I would think that the 275 watts is the total max output available before overload.


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## rkenney (Aug 10, 2013)

My understanding is that the post war ZW 275 watts is power consumption. Since there is some loss in power transmission of any kind this number is lower for power output.

The power master conditions the transformer OUTPUT up to its (Power Master) rating.


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## gunrunnerjohn (Nov 10, 2010)

The PW-ZW can deliver all of it's power to one output, though that's not necessarily recommended. However, the 275 watt rating is the input power rating, the output power is in the 220-230 maximum range. The older PW transformers were rated on input power, doubtless to make them sound more powerful.


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## Patrick1544 (Apr 27, 2013)

rkenney said:


> My understanding is that the post war ZW 275 watts is power consumption. Since there is some loss in power transmission of any kind this number is lower for power output.
> 
> The power master conditions the transformer OUTPUT up to its (Power Master) rating.


rkenney
If the Powermaster is only rated at 180w, what would happen to the reserve wattage in the ZW? As Gunrunner mentioned the est. output is around 220w. I wouldn't be using the full potential of the ZW output.


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## gunrunnerjohn (Nov 10, 2010)

You would certainly want a good 10A breaker between the ZW and the PowerMaster to protect the PM from possible short circuits. The ZW breaker is far too slow and it's rated at 15A as I recall.


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## Patrick1544 (Apr 27, 2013)

I do have some new 10A re-settable breakers and some TVS diodes to be included in the initial set up. Do I need a PM for each output that I decide to use for track power, on the ZW? Like A and D for instance would each require a PM?


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## rkenney (Aug 10, 2013)

Patrick1544 said:


> rkenney
> If the Powermaster is only rated at 180w, what would happen to the reserve wattage in the ZW? As Gunrunner mentioned the est. output is around 220w. I wouldn't be using the full potential of the ZW output.



You could. Simply because the Power master rating is limited below the ZW doesn't mean you can't run accessory circuits off the ZW separately.

Instead of worrying about driving your transformer at 100% output, I would simply put my effort toward making it work without excess voltage drops. People who get all wrapped up in theory often lose sight of basics. Function over theory.:stroke:


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## gunrunnerjohn (Nov 10, 2010)

Well, the primary use of multiple PowerMasters would be if you wanted to run two different tracks at the same time from the remote. First you need to define what the operating environment is.


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