ZW-L Quirk

I've owned the ZW-L for over a month now and its one fine transformer.  On my 16x13 layout, I have 2 main loops, plus sidings.  It powers all my track plus all my switches.  As others have reported, conventional engines do run better with it.  I have an FM trainmaster than can really crawl now.


I did manage to bring the ZW-L to its knees unexpectedly.  I was running 4 heavyweight lighted passenger cars pulled by a TMCC Pul-mor GG-1.  To get the GG1 moving the amps read 6 on the gauge.  The ZW-L starting flashing the red light indicating I was drawing too much power.  But I am only at 6 amps.  I should be able to go 10 amps before this happens.  The only way to get the red light to stop flashing was to decrease the power to the track from full power (18 volts) down to 16 volts.  Then the GG1 and its lighted cars ran perfectly.


I then tried to double head the GG1 with another TMCC GG1.  The amp gauge was reading 9 amps but the ZW-L was handling it - BUT only at 16 volts.  I could not bring the voltage up to 18 volts or the red light would flash.


I know the ZW-L can handle it but why not at full power?  I then tried other TMCC Pul-mor engines I had.  Same result.  With the 4 lighted cars in tow, I ran 2 TMCC gp9s.  At 18 volts to the track, the ZW-L would not let me pull more than 6 amps or the red light starts to flash.  Decreasing the voltage to 16 volts and it runs perfectly.


This problem only occurs with pul-mor powered engines.  I tested a can motor engine (TMCC K4).  I had to put 12 passenger cars on the track and the smoke unit on on the K4 to get the amps over 6 on the gauge. (Those can motors are really efficient!) But the ZW-L worked perfectly at 18 volts to the track and I was pulling over 6 amps.  I then double headed the K4 so I was pulling 7 amps.  No problems.  At full voltage to the track, it was handling the high amps (as I would expect).


For some reason at full voltage, I can not run a pul-mor powered engine if the amps go above 6.  It will work fine if I decrease the voltage by one or two volts.  Yet over 6 amps with a can motor engine at full volts and its fine.


I tested all 4 channels with the same result.  To eliminate any possible wiring issues with my track, I setup a test track.  The ZW-L, the legacy base, GG1 and the 4 cars.  Same result.


I called Lionel and they thought my ZW-L was having a problem.  They gave me another ZW-L and I sent my original to them for review.  I get the same results with the new ZW-L.  It appears to me that there is some quirk it has detecting the overload when a pul-mor engine is running.  Any TMCC pul-mor causes this problem.  I tried GP9s, Century Club S2 turbine, GG1, and K4 Torpedo.


The simple fix is just to decrease the voltage and all is good. 


Has anyone else seen this?

Original Post

Try putting a 10uf 50V non-polarized capacitor across the output of the ZW-L and see if that stops the transformer from tripping.  I saw the same kind of issue with some TMCC locomotives with the TMCC Direct Lockon, apparently some sort of noise was triggering the breaker.


Is the unit powering anything else at the time you tried to run the GG-1+ illuminated passenger cars?  The transformer can supply up to 180 watts to any given terminal BUT it has a top limit of 620 watts which is less than 180x4.  By dropping the voltage to the block you are trying to control the GG-1's with you are reducing the POWER delivered to the block and the red light stays off.  You can control the voltage but the current being used is based on the load seen by the outputs.

Quando Omni Flunkus Moritatum

Chuck:  In my testings, I was only using the one output.  All the other outputs were off.  That's why I also setup a test track.  When using the test track I only had one output connected.  I should have the full 180 watts @ 10 Amps available.


Chris: I originally emailed Lionel support (end of May) and discussed with Mike Reagan.  The engineer was thinking it was just my unit that had a problem so he wanted to look at it.  I informed Mike that the replacement did the same thing.  I tried to follow up and offered to speak to the engineer directly.  I never heard back from them.   And according to the email I got from Mike, Jon Z was not the engineer.  Jim was the engineer and he was looking at the problem.  Its my hope Lionel is still looking.  In the meantime I wanted to know if anyone else has seen this.  Since I can reproduce the problem all the time and with 2 different units, I think its some sort of quirk in the transformer.


I am not complaining about Lionel's support as they did send me a replacement.  I am very grateful for them doing that.   I offered to talk to the engineer who designed the unit but never got a response.  In fairness to them, I did say I could live with it, if that's the way it works but I did request to be kept in the loop since I can reproduce the problem easily.

I'm thinking the meter readings aren't all that precise.  Or the locos aren't predictably reducing their amperage draw proportionally when you increase the volts to 18V. These systems are far from linear.  It's total watts that are presumably tripping the overload circuit, and when you use 16V, your amperage draw is proportionally less rather than proportionally more than at 18V for some reason.  Hence the overload.  There's nothing magical about the meters if they're not reading true peak voltage or amperage, which I'm guessing they are not.  Somehow you're exceeding the overload setting at 18V, but not 16V with these particular locos.  May not be a flaw in the ZW-L, just too much power draw at 18V given the mechanical/electrical properties of the locos and the mechanical load put on them by these cars.

Try the 10uf cap I suggested, it's certainly not going to hurt anything, and if it's the electrical noise from certain engines as it was for me with the TMCC Direct Lockon, it may change it.  It's a quick test...


Do you have access to an external Ammeter?  Measure the draw of the passenger cars alone and then of the engine alone.  Open frame motors pull more than double the current of a can motored engine.  You have to power the field coil as well as the armature.  It is not uncommon for these to pull 50+ watts on their own.

Quando Omni Flunkus Moritatum

I sent an email to Jon to see what he has to say.  May he knows more about it.


John: Cap sounds like a good idea.  Don't have any lying around so I'll pick one up first chance I get.


Chuck: The cars alone pull about 2 amps sitting on the track when its at full power.  So at 18 volts that's only 36 watts. 


So far I have not heard if anyone else has see this which is what I was also curious about.

I  am very interested in this thread.  I have not seen this on my layout with my Pullmor locos or my ZW-L, and I would have noticed if it was occurring, but that does not mean it is not a future potential problem.  I hope someone gets to the bottom of this - and thank you for all the work in bringing it to everyone's attention.

Chuck: I'm going by the meters on the ZW-L.  I do not have a separate ammeter. 


Lee: Are you running in command mode?  The problem only occurs if the ZW-L is set to full voltage and you are running a pulmor motor and the amp reading on the ZW-L is around 6.  Can motors do not cause any problems.


I have the ZW-L set for command operation.  All four handles are set to max voltage.  I power up the ZW-L using the legacy remote.  I address track 1 and turn the red knob until the voltage meter reads max on the ZW-L.  Speed steps for the ZW-L is set to 200 for all 4 channels. 


My train room has a dedicated line from the Circuit Box - 20 amp breaker, 12 gauge wire to the outlet, powering the outlet.  Nothing else is on the circuit.  The ZW-L does go through a power strip.  I tried plugging directly into the outlet and it had no effect.

I suspect the meters are not reading properly with the open frame motors (they may not be ready correctly, period).  Everything you are describing indicates you are pulling current well over the 6 amps displayed.  Since  the train behaves if you back down the voltage to 16 I don't think this is a noise issue either.  I'd recommend getting a hold of a decent meter and checking the actual draw or try running that train configuration on a straight PH 180.

Quando Omni Flunkus Moritatum

I would think the locomotive would require more current to move at the lower voltage setting, so I'm not sure I agree with the analysis that this has to be an over current issue only at 18 volts. 


I tested a Pulmore motored locomotive with four lighted 15" passenger cars at 14, 16, and 18 volts track power.  The start-up and running current for the same observed speed was more at the lower voltages in every case.  This was using a pure sine wave transformer and a Fluke clamp-on ammeter.


I think something more than simply over current is in play here.  I could certainly be wrong, but I wouldn't bet all my money on lower current at lower track voltages, especially during start-up and attempting to maintain the same speeds.


I'd still like to see the noise suppression cap tried.  I'm not saying it'll solve the problem, but the process of debugging is simply removing possibilities until only one remains.


Hey John,


The Heavy weight passenger cars I'm using have 4 bulbs per car.  So they are power hungry.  If you have the time, maybe you feel like a road trip to me in Malvern and you can bring your meter along to see whats going on?  And of course - run some trains!


Email me if interested.


One thing that confuses me..

I added a second gg1 to the load, and at 16 volts, I can run 2 GG1s and the passenger cars and the ZW-L doesn't miss a beat.  Its amp meter reads around 8-9 amps.  I would think that that load would be too much handle but it handles it.

If you subtract one car from the consist does the train run OK at 18 volts?


The ZW-L is not a pure sine wave power source and the actual instantaneous power the consist is trying to pull is just over the 180 watt max when the throttle is set at nominal 18 volts.

Quando Omni Flunkus Moritatum

Originally Posted by Joe Fermani:


Lee: Are you running in command mode?  The problem only occurs if the ZW-L is set to full voltage and you are running a pulmor motor and the amp reading on the ZW-L is around 6.  Can motors do not cause any problems.

No, I run conventionally. 


First, I know that because of its chopped waveform outuput - the "volts" reported by the ZW-L's meter are not equal to normally measured volt readings, and that the numerical indications on the throttles are not exactly corresponding to output "voltage."  STill, I will refer to both below as voltage. 


I have not had this identical problem, but I have had one recurring problem(that is not going to go away) with the ZW-L  with Pullmor motored locos.  I have it to the largest degree with the Lionel Santa Fe Anniversary passenger set: the A-B-B-A engine set has, I think, four Pullmors, and I've added two incandescent lighted cars to the seven car set.  Liberal use of throttle (up to say, 16 or 17) when this train starts out will trip the ZW-L's 10-amp breaker: the "locked rotor" current draw of the Pullmors at, say, throttle level 16, plus the lighting gets me a nasty red over-current light and then trips the breaker in short order.  I've learned to ease the throttle up to about 13 "volts" (or whatever the meters are actually reading, which barely gets the motors' attention and just barely moves the train - with a lot of groaning, then to gradually increase throttle now that the rotors are turning a bit.  This actually flashes the red over-current warning light for about three seconds but it never trips. 
     This same train did not cause this same level of heartache with Z4000 I had before.  Yes, I could trip the Z4K's 10-amp breaker with a quick start at very high voltage (snapping the throttle to full when the train was standing still), too, but a normal start requiring only about 16 volts which gave its digital current reading to about 9.5 amps and the breaker never got excited about it. 

     I think the ZW-L's chopped waveform output, while just fantastic for powering can motors slowly and linearly, runs into "linearity" or reactive power issues with the Pullmor motors AC field magnets, etc.  I think this causes the ZW-L a bit of heartburn and perhaps to misread its power output slightly.  This probably causes more that just heartburn when you run digitally since there, the throttles are advanced to the max


Sorry I can't be of more help.

My thinking is that maybe the detection method for overcurrent in the ZW-L is a lot more picky than the Z4000.  I believe the Z4000 uses a fairly standard breaker circuit, and I suspect the ZW-L is using an electronic circuit similar to the TMCC Direct Lockon or the PowerHouse 180 transformers.


Another thought, however remote, is there something more than plain light bulbs in the passenger cars?


Joe, do you still have the Z4000?

I never owned a z4000. I have a 180 brick and a type v transformer .  I also have a zwc with 135 bricks


LOL.  I thought about that too.  I opened one of the cars and its just 4 bayonet bulbs.

I tried what Chuck suggested and I took one of the cars off.  I could replicate the problem with 3 cars as well.

Originally Posted by Don Trinko:

meters have fairly slow response so you may not see peaks near 10 amps. Don

Analog meters (REAL TIME) have "slow" response???  They must be VERY highly damped.


The analog (safety related) meters I have monitored in a Power Plant control room always instantly fluctuated around the mean value.

I tried the GG-1 with a 8 car freight in tow.  ZW-L red light still flashes when set to 18 volts.  I then pulled out my tmcc gp9s (double a units 1 pullmor in each unit).  Took the GG1 off and put the gp9s on the track. 


The red light did not flash BUT the engines bucked and surged and ran horrible.  I dropped the voltage down 2 volts and the gp9s ran smooth as silk.  And they were not pulling any cars.

So I hooked up the 180 brick to the track and disconnected the ZW-L.  Tried the GG-1 and it worked perfectly.  I then tried the GP9s.  Also worked perfectly.  I even tried running the GPs and the GG-1 all at the same time.  The 180 brick performed fine and no tripped breaker.


I then tried the GG-1 by itself powered by the ZW-L (set at 18 volts).  The ZW-L flashed the red light. 


Brick is 18 volts, sine wave.  ZW-L is not a sine wave and I believe the peak to peak voltage is actually higher than 18 volts.  I think it was identified as more like  22 volts in one of the video's?  The ZW-L is also monitoring more than current.  It is checking on actual power consumption (current times voltage).  At this point in time I can't ink of a reason for the apparent false positive on an open frame motor at 18 volts.

Quando Omni Flunkus Moritatum

Chuck, if the ZW-L is really able to put out 180 watts on a channel, the peak voltage shouldn't really be much of an issue. If it's putting out a higher peak voltage chopped waveform, it still shouldn't be exceeding an average power of more than 180 watts.  If it is, then I would consider it a poor design for it's intended purpose.


Also, since I believe 18V is close to full throttle setting, the output waveform should actually be pretty close to a sine wave with only some minor truncation on the trailing side.


Nothing in this thread has convinced me that we don't have a possible electrical noise issue.  I don't say that's a certainty, only that it's one possibility.  It seems clear that the test locomotives are not pulling anywhere close to 180 watts, so the operation of the ZW-L is suspect with the AC motors at the very least.



He's not tripping the breaker or shutting down the channel.  a.k.a. he isn't actually exceeding the capabilities of the transformer.  All that is actually happening is a red light is blinking rapidly.  


Why is the detection circuit triggering at 18 volts and not 16 volts?  Why would there be noise at 18 volts and not 16 volts?  The test with the brick confirms he is well below the current limit and the test with removing the passenger cars re enforces this isn't an overload.  I don't know what the detection circuit is looking at but it seems to be triggering a false positive.

Quando Omni Flunkus Moritatum

I agree it's a false positive, and I freely admit without further analysis that none of us really know why it's happening.  The point of recommending the PH180 test was to insure that it wasn't a real overload.


Actually, when the light is blinking, the voltage is reduced, which is why he's seeing the surging of the locomotive.  From the ZW-L user's Manual.


When there is a short on any of the outputs it will reduce the voltage on that output in a fraction of a second to hold the current at 10A. If the short circuit is not corrected in 3 seconds the transformer will interrupt power to that output.

I believe this voltage reduction is what causes the surging he mentions.


Another possibility is the power factor shift when running AC motors, that may be triggering the over-current sensing.



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