ZW Amp/Volt meter TVS

It depends on what you are trying to protect.

I would just put the TVS on the output of the meter. It won't fit correctly under it and you don't want loose connections heating up since power has to go through the meter system. Again, they way they built those, the meter has to be connected right on the transformer without any interference.

Also, if being totally transparent with you, I'm not impressed with those add-on ZW add on meters now that I know how they work. They cannot measure current of the individual channel unless serious modifications are applied. To me current is far more important than voltage. A light bulb gives me a huge clue how much voltage, but even with that meter- current - all you know is how much the combined current is and in a lot of cases and troubleshooting- that's just not all the helpful. Don't get me wrong, it looks cool, and sure I'm not saying they have no value, but the cost (those things these days being semi rare sell often way over MSRP) and the limitations of that add-on meter, definitely didn't meet my expectations or needs.

As always, your railroad and your wallet.

Rob,

I trying to protect circuit boards that are in a few of my locos.

Vernon,

I agree that the current is the most important. One reason I want the voltage is to run my two Lionchief locos at about 16 volts. Its hard for me to see the marking on the lever. I know that at about 16 1/2 is putting out 16 v according to my little VOM. I already bought the meter on ebay.  And like you say is looks good, even with the scratch. We have one at our club and it helps me some.

Do you have any other ideas on the common binding post caps?

Could you point me to the "unless serious modifications are applied".

Thanks so much for you wise council!

@Santa Bill K posted:

Do you have any other ideas on the common binding post caps? Not really and I think the insulation is overkill/cosmetic. It's just 4 nuts to make the electrical contact to each post. Since they are in a recessed hole, it just makes it easier.  Again, the insulation is more cosmetic than anything.

Could you point me to the "unless serious modifications are applied".

See this topic https://ogrforum.com/...amp-meter-attachment

Note, the early ZW version is 6-14077, where as meter part number 6-14002 is for the more modern ZW-C style units.

I think the current sensing mod is just putting a switch so that only the track being measured is "in circuit". The reason why that is hard or harder is we tend to make layouts all common and then wiring that to the meter so you get both voltage and amperage readings. Again, because the whole thing originally mounts to the transformer, well that complicates it.

@Santa Bill K posted:

.. trying to protect circuit boards that are in a few of my locos.

Put the TVS diodes across the AC input(rollers & chassis) to the few locomotive control boards, then you won't have to worry about where you're running them.