Lionel ZW Volt & Amp meter attachment

They work OK, but don't count on the current readings to be accurate, they stupidly used the common to measure current.

gunrunnerjohn posted:

They work OK, but don't count on the current readings to be accurate, they stupidly used the common to measure current.

John,

Was this also true of the units made for the newer ZWs?

Yep.

H1000 posted:

...

Was this also true of the units made for the newer ZWs?

Yes... I used them on two ZW-C's, and they were a royal pain.  It was a great idea, and they looked cool in the catalog.  But the person designing them didn't have a clue how most folks use a ZW.  So typical of the miscommunications between Lionel Stateside and their Chinese factories.    I think that was the same team who screwed up the first batch of 180W bricks, and Lionel subsequently needed to supply adapter plugs to invert the wiring polarity when attaching the bricks to the ZW-C's.  The whole thing was one big kludge... which was really sad, since it was the "first" ZW solution Lionel brought to market after the venerable postwar ZW's were aging and many had seen better days. 

It took awhile, but at least Lionel got it right 15 years later with the ZW-L.

David

Mine works fine on the post war ZW and the one on the ZWC. The current is not accurate but is generally useful. The voltage readout is the important readout and works fine.

You may have to replace the rechargeable 9 volt battery when you get it. 

I think these were a case of Lionel trying to keep up with the Z-4000s that have integral meters.

Hmmm..... So they work and the reading for current is only accurate if you only use one channel or as long as you make sure the commons are separate on your layout (hard to do with modern layouts).

I might still give one a chance, he is selling it pretty cheap.

I tried one years ago and it failed quickly.  I found it much better as John would say to roll my own and mount meters from digikey in small cases.  This also allows for mounting circuit breakers and TVS.

Bill

ogaugenut posted:

I tried one years ago and it failed quickly.  I found it much better as John would say to roll my own and mount meters from digikey in small cases.  This also allows for mounting circuit breakers and TVS.

Bill

You didn't help my decison making process! Cheap is good but I think what you may have built is not only better, but even cheaper.

Would you be willing to post some pictures and parts list?

gunrunnerjohn posted:

They work OK, but don't count on the current readings to be accurate, they stupidly used the common to measure current.

Is there a way to modify that if I am somewhat electrically inclined? I have been using mine with isolated loops and it seems to work fine.

I modified the plugs on the back to add banana plug attachments but haven't found a solution to put banana plugs on the posts along the bottom. 

George

George S posted:

gunrunnerjohn posted:

They work OK, but don't count on the current readings to be accurate, they stupidly used the common to measure current.

Is there a way to modify that if I am somewhat electrically inclined? I have been using mine with isolated loops and it seems to work fine.

I modified the plugs on the back to add banana plug attachments but haven't found a solution to put banana plugs on the posts along the bottom. 

George

Well anything can break, but as to the current, the current sensors are all in the U or common leads and then all the U terminals are connected together. So I think the total current is right, but as to how it divides is a guess. Dale Manquen did a review of the meter, I'll look for it.

Here's Dale's 

http://www.trainfacts.com/trainfacts/?p=378

I have three of these meters and they all work fine. I did replace the rechargeable 9 volt battery in one of them. Also when you get it, do not use a screwdriver on the black bakelite hold downs for the wire rings, just tighten them with your fingers or they will break.

I was tempted to buy the ZW-L to replace my ZWC, but it has two serious flaws for me. The first one is that you have to turn the throttle on the CAB2 every time you want to go to the 18 vac when you turn on or recover from a fault. With the ZWC you can leave the handle at 18 vac and just turn the transformer on. To recover from a fault, just turn the transformer off and back on. I do this remotely with a Bluetooth device connected to the power for it. My second gripe is the tiny analog meters...and having them have to switch outputs since there are only 4 meters instead of 8. The digital meter can be seen across the room and are on all the time for each handle.

I put the ZW-L in Nassau's sale (15 % off) cart twice last night and took it out both times. I just couldn't bring myself to sacrifice utility.

I like the Red digital meters too. 

I do a lot of floor layouts and ad hoc setups.  I made a number of meter modules out of wood and masonite.  These are standalone modules with terminal strips for connection and are totally oriented to temporary set-ups.  I will not do it this way  when I eventually build a permanent layout.   Stylistically, these are like a 1960s control panel and fit with the feel of my layouts.  There are lots of options on how to build the housing.  These are  useful in a lot of different ways in different circumstances.  I also built some voltmeter only units.

I 'm sorry I don't have a part list.  A lot of the parts were left over from the wiring of a boat and I used them because I had them.  The breakers are Blue Sea marine, they usually blow faster than the ZW breaker.  Also, I built modules with different breaker values.  The TVS is the standard one that GRJ recommends.  I did not do the 22uh chokes, but would look into that were I to do it again (I do run command and conventional).  The left over analog meters were not lit, so the ones in the photo are side lit with LEDs.

Bill

H1000 posted:

I might still give one a chance, he is selling it pretty cheap.

Go for it. I'm using mine on a 1948 ZW.   An interesting dichotomy.

Dale's analysis is spot-on, that's what I was saying.  Having independent current sensing coils for each U connection would solve the problem, but of course that would have run up the cost a bunch.

It does have individual sensors on the U side, but they should have been on the ABCD side. Because the ABCD wires are not connected together. That is the mistake. I wonder if the decision to put them on the U side is a circuit issue rather than a blind mistake...kind of like the issues of powering digital meters with the voltage you’re measuring.

I'm sure it was a cost driven decision, and probably ignorance of how the transformer is used.  If you had them on the ABCD side, you'd have to have true circuit isolation for each current measurement channel.  Having them on the common U terminal side, there was no extra isolation needed.  That just wasn't a workable solution for the way the transformer is used in 99.9% of the installations.

H1000:

If you decide against purchasing these meters, would you please email me using the one in my profile as I could use several.

I have been using the ZWC with these type meters for over 15 years without a single problem.  I know the amp meters are tied together but you cans certainly isolate a problem using them by cutting power to all but one channel.  The large numbers allow the ability to check status from 10 to 15 feet away.

Not ever thing is perfect for every situation but I find buying the ZWC meters one of the best $120 decisions I have ever made in the hobby.  I have helped friends install seven of the ZWC with meters without any issues.

I would have emailed you but your email is not in your profile.

Thanks and happy railroading,

Don

cjack posted:

It does have individual sensors on the U side, but they should have been on the ABCD side. Because the ABCD wires are not connected together. That is the mistake. I wonder if the decision to put them on the U side is a circuit issue rather than a blind mistake...kind of like the issues of powering digital meters with the voltage you’re measuring.

I think it was a mechanical engineering decision. The U posts are right there. The ABCD posts are outside the meter enclosure. The whole unit would need to be redesigned to make it that easy to install. The problem started when Lionel put the U posts above the ABCD posts on the ZW.

George

cjack posted:

I was tempted to buy the ZW-L to replace my ZWC, but it has two serious flaws for me. The first one is that you have to turn the throttle on the CAB2 every time you want to go to the 18 vac when you turn on or recover from a fault. With the ZWC you can leave the handle at 18 vac and just turn the transformer on. To recover from a fault, just turn the transformer off and back on. I do this remotely with a Bluetooth device connected to the power for it. My second gripe is the tiny analog meters...and having them have to switch outputs since there are only 4 meters instead of 8. The digital meter can be seen across the room and are on all the time for each handle.

I put the ZW-L in Nassau's sale (15 % off) cart twice last night and took it out both times. I just couldn't bring myself to sacrifice utility.

Put it back in the cart. Go for it. You’ll be glad you did. Great transformer.

George S posted:

I think it was a mechanical engineering decision. The U posts are right there. The ABCD posts are outside the meter enclosure. The whole unit would need to be redesigned to make it that easy to install. The problem started when Lionel put the U posts above the ABCD posts on the ZW.

While that may have been a factor in it ending up the way it is, it's still stupid!  When you're designing a retrofit product, one of the goals is to make it functional in the intended environment!  This product fails in that regard.  Virtually all layouts have common ground everywhere, so the only way to measure current for each output properly would have been to monitor the individual  A-B-C-D outputs, and not the common side. 

I suspect someone that had no involvement in the model train hobby designed the meter attachment and just "assumed" that each common would be isolated.  Anyone that's every wired a real layout would know better!

gunrunnerjohn posted:

George S posted:

I think it was a mechanical engineering decision. The U posts are right there. The ABCD posts are outside the meter enclosure. The whole unit would need to be redesigned to make it that easy to install. The problem started when Lionel put the U posts above the ABCD posts on the ZW.

While that may have been a factor in it ending up the way it is, it's still stupid!  When you're designing a retrofit product, one of the goals is to make it functional in the intended environment!  This product fails in that regard.  Virtually all layouts have common ground everywhere, so the only way to measure current for each output properly would have been to monitor the individual  A-B-C-D outputs, and not the common side. 

I suspect someone that had no involvement in the model train hobby designed the meter attachment and just "assumed" that each common would be isolated.  Anyone that's every wired a real layout would know better!

Agreed. It would have been nice if they designed it to cover the entire back of the unit and added banana jacks and measured the current from the ABCD posts. It may have even been easier to install.

That said, I still wonder if there is a way to modify it by insulating the connection on the common posts and adding jumper wires to switch the connections for each meter. Would that mess up the voltage readings? I would think it wouldn't matter with AC output. For example, if I took the unit off the ZW and jumpered the connections onto the ZW switching what connects to U with the leads that go to ABCD, would it work then?

George

I wondered about cutting traces and moving the current sensor up to the ABCD areas, but Dale opted for additional sensors in that area. I figured he would have been the one to know the most functional way to modify it.

I'm sure Dale had diagnosed the easiest way, it's not a simple fix.

George S posted:

...For example, if I took the unit off the ZW and jumpered the connections onto the ZW switching what connects to U with the leads that go to ABCD, would it work then?

This is the method I just have not had time to try, although every time I revisit the idea - like you just reminded me - it seems like it would work.  It would just take 16 or so sets of alligator jumpers to give it go!

ADCX Rob posted:

George S posted:

...For example, if I took the unit off the ZW and jumpered the connections onto the ZW switching what connects to U with the leads that go to ABCD, would it work then?

This is the method I just have not had time to try, although every time I revisit the idea - like you just reminded me - it seems like it would work.  It would just take 16 or so sets of alligator jumpers to give it go!

I took mine apart to look at what it would take. It doesn't seem too complicated to change it, but I worry that some of the electronics are polarity sensitive. The meter gets its power from the posts on the back of the ZW. There is a battery charging circuit, though. I am sure that is converting AC to DC to charge the battery. I wouldn't think it would be sensitive to whether the input AC was reverse polarity. In fact, Lionel had those old PH 180 transformers with the phase reversed, and to my knowledge, those did not destroy any meters. I had a couple of those that I have since fixed. I think I will let one of you guys try it first though. These aren't the easiest things to replace. BTW, you can use machine screws and hex washers if you on most of it if you don't have enough alligator clips. 

One thing I did do was finally modify the ABCD posts to add banana jacks. Here's a pic. 

I bought these speaker binding posts at Menards. I removed them from the white plastic insert and they screwed tightly onto the extended post. I added the brass compression screw back onto the post, just to make sure it wouldn't slip. This was an easy conversion. I just wish I could have bought the four red ones I needed instead of the whole package. I did try putting them right on the original posts, but they were slightly loose, and I thought they might not hold the meter jumper wires tightly in place.

One last thing, there was no soldering required in the installation of either set of binding posts.

George

George S posted:

I worry that some of the electronics are polarity sensitive...

 That's the least of my worry, there is no polarity sensitivity in the AC output of a ZW.

I see some value in  ZW voltage and amperage add on. While you do not know the amperage use of each transformer winding, you do know the total current draw, useful for knowing that you are not exceeding the boxes wattage rating.

ADCX Rob posted:

George S posted:

I worry that some of the electronics are polarity sensitive...

 That's the least of my worry, there is no polarity sensitivity in the AC output of a ZW.

Well then, it should work. I'll give it a shot when I get some time. 

George

Here is how I am thinking about tackling this. The screw posts indicated by the #1 arrow connect to the U common posts on the ZW. They have a brass inner end that makes the primary electrical connection to the meter. That circuit feeds through the current sensing circuit to the black posts above. The small wires on the bottom connect the meter to the ABCD posts.

The objective is to feed the ABCD power to the meter pickups behind the #1 indicated screw posts. This can be done by using a jumper wire from the ABCD posts to the current sensing meter pickups. Those meter pickups will need to be insulated from the ZW U posts, and the small wires coming out of the bottom of the meter will need to connect to the U posts. The top row of connectors on the meter will then become the ABCD outputs, which I think should then be changed to red. It appears the screw posts indicated by the #1 arrow in my picture will need to be replaced, because that will be the place to get the common connection. The extension studs that I attached my red banana jack posts to could be used instead, but I will need to find a fiber washer to insulate the meter pickups and a short length of plastic tube to make sure the portion of the post behind the fiber washer is completely isolated from the meter pickup and the jumper from the ABCD posts. Otherwise, I will have a nice short circuit. Good news is that the ZW and the power supply have good protection from shorts. I'm not sure about the meter.

George

Before getting too convinced that you can easily make the meter measure the hot terminals rather than the common terminals, try the following-

1. Remove the meter from the ZW. Lay it on the table with no wires connected to any terminals.

2. Measure ohms between the various common terminals (UA, UB etc) on the meter. I suspect you will see a very low resistance, much less than one ohm.

If my guess is correct, putting the meter in the hot terminals will effectively short them all together, which won't do the transformer or the meter any good.

I would venture to say that Lionel did it the way they did so they wouldn't need an isolated power supply for each channel of the transformer, and wouldn't need current transformers. It is similar to the situation with the inexpensive digital panel meters, you need a separate isolated power supply for each one,

Or so I suspect.

PLCProf posted:

Before getting too convinced that you can easily make the meter measure the hot terminals rather than the common terminals, try the following-

1. Remove the meter from the ZW. Lay it on the table with no wires connected to any terminals.

2. Measure ohms between the various common terminals (UA, UB etc) on the meter. I suspect you will see a very low resistance, much less than one ohm.

If my guess is correct, putting the meter in the hot terminals will effectively short them all together, which won't do the transformer or the meter any good.

I would venture to say that Lionel did it the way they did so they wouldn't need an isolated power supply for each channel of the transformer, and wouldn't need current transformers. It is similar to the situation with the inexpensive digital panel meters, you need a separate isolated power supply for each one,

Or so I suspect.

Good point. Maybe I should leave well enough alone.

I built my own meter panel for use on a layout, and I have isolated power supplies and isolated measurement of the circuits. I use that with a DCS setup where my commons are tied together. I really only use my ZW when running carpet loops.

George

I see PLCProf beat me to it, I was going to point out the likelihood of bad things happening by turning things upside down.  I still think that Lionel was simply saving money by doing the current measurement the cheap way with a common ground, inverting it would very likely do exactly what PLCProf says, short things out, fire and brimstone!

H1000 posted:

gunrunnerjohn posted:

They work OK, but don't count on the current readings to be accurate, they stupidly used the common to measure current.

John,

Was this also true of the units made for the newer ZWs?

John,

Can we at least count on the voltage to be accurate. Did the designer and approver have electrical engineering degrees?

Hard to know what degree the guys that build these had, but I suspect not much experience with model railroading!

I suppose for the PW-ZW the voltage should be fairly accurate.  However, given the fact that the ZW-C puts out a sawtooth waveform, I wouldn't count on the voltage measurement being all that accurate.  Hard to believe they are doing a true-RMS measurement in that meter assembly, so getting accurate readings of the sawtooth waveform probably isn't in the cards.

I use them to see which Powerhouse tripped out and if the voltage is 18 vac (which is fairly accurate at full output). Easy to see across the room and see if the total current is reasonable. There is a lot of value in these meters if you know the limitations.

One of the sponsors has the Powerhouse for $89.95 in stock