Phasing Question

From how you describe everything that is odd. I am not really sure what's going on but I have one idea. Is the ZW plugged into the same 120VAC outlet as the PowerHouse's or even in the same power strip or a completely other outlet?

Are all the grounds tied together?

Do you get the 18VAC differential between the commons with all the ZW Common-A-B-C & D wiring disconnected? 

Zachariah, the ZW is plugged into the same power strip.  Hokie, the ground from the PM is connected to the ground on the ZW above the A post.  Bob, I'm not sure what you mean.  I did have all of the ZW grounds tied together.  I removed the connection between the ground above the A post and the ground above the B post for the test.  Should I remove all ZW ground connections?

FWIW - The four U posts are connected internally.

This maybe a really dumb questions but are the Powermasters actually putting out voltage when you are doing your test?

Marty

It is not a really dumb question at all!  Until I tested again with your question in mind, I did not realize that I had to actually activate the Powermaster with my Cab1.  Duh!  I'm really embarrassed with a very rookie mistake.  With the Powermasters activated and testing at 18 volts each, I performed the phasing test again by connecting the common from each Powermaster in turn to the ZW.  I turned the ZW throttle to 18 volts.  My first reading was 19 volts for each PM to ZW.  After switching the ZW plug orientation, my reading was .101 volt for each.  Therefore, can I assume the second plug ZW orientation reveals the neutral end and provides phased transformers.  I will mark the neutral end for future reference!  Thanks to all responders.

A classic “DUH” moment. I’ve had thousands of them.

Glad you got them phased.

This is just an opinion so don't shoot the messenger...but using a post-war ZW with modern electronic locos is probably not your first choice. The fusing is too slow and there can be other issues like the voltage going up when the whistle or horn buttons are pressed. Maybe you already added external, fast-acting protection devices to your track blocks ahead of the ZW. If not, I think you should consider it. Or just run all your track on 180W bricks and use the ZW for accessories, etc. I love the ZW as much as anybody (hey, my blood is red!) but we have to be realistic--and safe.

Don Merz

@Don Merz 070317 posted:

This is just an opinion so don't shoot the messenger...but using a post-war ZW with modern electronic locos is probably not your first choice.

@Richard Whipkey posted:

I am adding a post war 250 watt ZW to add auxillary power to operating tracks and uncoupling tracks, accessories and lighting.

And of course, the 180 watt bricks pose the same threat to electronics as the ZW, as neither has the needed Transient Voltage Suppression.

Don and Rob

Thanks for the input.  My ZW does not control any track power.  My trains are all powered by the bricks.  Every connection to the tracks off the bus lines from the bricks has TVS added.  The ZW will only power operating and uncoupling tracks as well as accessories and lighting.  Nonetheless, I have added fast acting fuses in line from the ZW and it has TVS protection between the power and neutral connections.  The power to the magnets in the uncoupling and operating also has PTC protection added inline.  The PTC fuses are resettable.  I have read that if a TVS is thrown open, one will have a short.  But, how do I find the open TVS?

@Richard Whipkey posted:

I have read that if a TVS is thrown open, one will have a short.  But, how do I find the open TVS?

They usually fail shorted, not open, that's easy to find. Otherwise you will need a scope to test for failed-open.

Sorry, Rob, I stated that backwards.  If I have one at every track connection, how is it easy to find?

@Richard Whipkey posted:

... how is it easy to find?

The heat. And smoke.

In actuality, you should have your power districts blocked so you can isolate & find any short circuit in quick order.

Thanks Rob

I do have my layout blocked into 16 power districts, so I shouldn't have too much of a problem finding a failed TVS.  Some blocks have more leads than others due to their length, but it should narrow it down.  I believe I read somewhere that the failure rate for TVS's in relatively low anyway.

Theoretically TVS diodes can withstand a infinite number of events but that's not realistic. When they fail shorted that's easy to find out. If they fail open the only way to know is if you remove the diode from the circuit (track) and test it you self. If your interested in testing a TVS check out this thread HERE