Post war ZW transformer circuit breaker pops after 5 - 10 minutes of running 3 trains simultaneously; what's up?

Only you can tell. Take a meter and measure the total current in Amps. Multiply by the voltage (use 15 Volts as an example)  The answer is the power being consumed in Watts.  A ZW will supply around 200 Watts on a good day in a cool room.  This is the simple method to get a rough idea of the power being consumed.  

If you don't have an ammeter that will measure up to and beyond 10 Amps, measure each train by itself and add them up.

If you divide 200 by 20 (Watts by Volts) you get 10 Amps. I don't know what the rating of the circuit breaker is, so you need to look it up or ask someone who might know.  If your total power exceeds 200 Watts, I would imagine that the cb is doing its job. I would not suggest using a cb that is rated for higher current.

I would get a second transformer.

Dave,

Perform the math Arthur has prescribed above. If you are over 10A or so, you need more power (Why not another ZW - just put it in phase with your current one). If you are under 10A, your circuit breaker may be worn out. They are easy to replace. Depending upon your ZW, you can use one of the three:

Z22: 

ZW-232:

Modern Automotive Bussmann 19115 assembly: 

I would suspect poor track conductivity:  either between sectional track connections or electrical connections to the track, or both.  Or poor maintenance of locomotives; i.e. dirty wheels, track, rollers. etc.

Something other than the engines and passenger car lighting is sucking up amperage.

Drummer3 posted:

Are my trains drawing too much current for a 275 watt ZW?  Here's what I am running :

1.  MTH PS1 Hudson with 4 MTH lighted passenger cars.

2.  Lionel Silver Spike passenger set - both diesels lighted as well as 3 lighted passenger cars.

3.  AF passenger train (1992), both diesels lighted and 4 lighted passenger cars.

The circuit breaker automatically resets after about 2 minutes, I guess when it cools down.

Do I need to put in a higher amp circuit breaker perhaps?

Any suggestions appreciated. 

First question: yes

Second question: only if you want to fry your electronics/start a fire on your layout....

During the 1990s I was still using 3 pw ZWs [each on separate tracks] all of which at one time or another when loaded at 8-9 amps on my high shelf railroad, tripped out after about 20 minutes of continuous running. Based on my AC Ammeters,wired indivually on each power district[track], when converted to watts, it indicated 180-190 watts  was about maximum load for my well maintained ZWs when running continuously. Typically I ran two trains on the same track, usually one was a long lighted unit of 10-11 cars.

Eventually changed over to 180 watt PoHos , TMCC and changed to LEDs in lighted passenger cars--no further problem with tripping.  Just as info,180 PoHos [bricks]have the fastest reacting circuit breaker of any transformer I have ever used.

"I would suspect poor track conductivity:  either between sectional track connections or electrical connections to the track, or both."

Could you explain how adding resistance to a circuit would increase current draw?

Eleven lighted passenger cars and four engines?  They may not be over the 200 watts, but I'll bet they're getting close.

Another possibility is the old circuit breaker is failing or at least mis-adjusted.  The way to really test this is to do a load test on the bench.  What used to be a good load is old automotive headlight bulbs, they are in the 50-60 watt range.  That transformer should be able to light three of them indefinitely at 12-14 volts output.

This evening I measured the amperage on the 3 loops I am using.   They all read 1.7 - 1.9 amps, or just under 6 total when all 3 trains are running.  So, perhaps the 10 amp breaker  is faulty.   What does 6 amps convert to in watts on this transformer?  Also, is it truly 275 watt output as stamped on the transformer?

 Another idea is to do away with the internal breaker and install external breakers, that is,  give each output post (A B C and D) its own external breaker, perhaps a 5 amp on each??

Well, the 275 watts in input power, that's how PW transformers were rated.  For continuous output power, figure on around 75% of that, and that's at full throttle.

If you're only drawing six amps and the breaker is tripping, time to replace the breaker.  Many folks use an automotive cartridge type breaker as a replacement, if you use a socket, you can even tinker with the rating of the breaker easily.

Dave, based on your readings, your internal breaker is worn out. You definitely should replace it with one of the ones I previously mentioned and not simply bypass it. You are free to add additional breakers to each individual output, and many would correctly state that would be best practice to do so (to protect against cross output currents), along with TVS diodes (such as 1.5KE36CA). Additionally, the 275 Watt rating is house current power consumption. Best to assume about 75% efficiency, hence the 200W output Arthur mentioned.

The Lionel test specs for the ZW transformer is that it should put out 30 amps for 11 to 40 seconds before the breaker trips.  It sounds like you are no where near this.  So the breaker is probably worn out.  There are lots of replacement options. 

Sounds like I will try the 10-amp automotive type breaker, and add an external TVS on each post.  Thanks for all the tips!

Dave, for what it is worth, the ZW breaker is actually 15 amps.

 Another idea is to do away with the internal breaker and install external breakers, that is,  give each output post (A B C and D) its own external breaker, perhaps a 5 amp on each??.

For safety's sake, the internal circuit breaker should remain, and be working properly. Down the road, that transformer will fall into someone else's hands, who will not know that the breaker has been removed. It could even be a family member. That written:

David Johnson wrote:

The Lionel test specs for the ZW transformer is that it should put out 30 amps for 11 to 40 seconds before the breaker trips.  It sounds like you are no where near this.  So the breaker is probably worn out.  There are lots of replacement options. 

That is a lot of power for a long time.
The internal ZW circuit breaker is there to protect the transformer, not your trains or layout wiring. Plus, it is fairly easy to accidentally create a circuit that is not protected by the internal breaker. I always put an individual breaker on each "Hot" output, terminals "A" through "D". I like to use Lionel postwar #91 adjustable electromagnetic, manual reset circuit breakers. There are many choices.
If any of your trains have circuit boards, a TVS on each output is a good idea too.

I'd say, the ZW's are doing what they are supposed to do - protecting.

The "trippers" are the passenger consists. Too many light bulbs, I concluded, during a personal experience running my layout.

In my limited personal experience in this regard, I have used these 5 ZW's (10 trains altogether; 2 per ZW, using only the two large handles on each for trains,) since inception of the layout in 1995. The only time the ZW's have given me any grief was when I tried to run (TMCC) TWO (8-10car) passenger trains on the same track. The ZW responsible for the initial trip-out went out after, approx. 3 minutes.

Then, I changed both trains over to a different ZW; same result - tripped-out.

It wasn't the two steam engines on the same track and ZW arm that were pulling those passenger consists that seemed to be the critical factor, because as soon as I changed one train over to freight, no problem with tripping.

My conclusion? Though the lighted windows seem innocent enough, they apparently add up to quite a drain. Thus, they trained me  and I modified my behavior to not run two passenger trains on the same ZW handle.

FrankM, Moon Township

P.S. For more particulars, I refer you to my betters, above, like CW Burfle. Those guys know lots of stuff. I just want the trains to move and look good doing it,; beyond that, my usual reaction is "Huh?'", and I call over to the house a specialist (he's the guy who designed and installed that ZW cache, as well as wired the entire layout, with connections every 4-6 ft. along all the ten independent loops.

bmoran4 posted:

Dave, for what it is worth, the ZW breaker is actually 15 amps.

Yes, but considering that's more than the ZW can actually usefully deliver, 10 or maybe 12 is a more realistic value.  The old PW breakers were just there to keep the transformer from frying, and they didn't even do that all the time.   A 10A thermal circuit breaker will tolerate a 20% overload for quite a long time, so a 15A breaker is way more than necessary for the ZW, at least IMO.

 Moonson posted:

My conclusion? Though the lighted windows seem innocent enough, they apparently add up to quite a drain. Thus, they trained me  and I modified my behavior to not run two passenger trains on the same ZW handle.

You need LED lighting, then the passenger cars will be light freight cars, no power issues.

I understand that LED lighting needs very little power,  but still, my 3 fully lighted passenger trains only draw 1.7 amps each.   Does anyone know how many watts that is?

  I am guessing about 40 watts per train ??

So, 3 trains x 40 watts each = 120 watts, which is way under 200 watts that the ZW can supply.

W=V*A

14V at 2Amps is about 30 Watts, or ~90 Watts total.

18V at 2Amps is 36 Watts, close to your 40 estimate.

Your internal circuit breaker seems to be worn out and needs to be replaced with one of the ones I mentioned way above at the beginning of this thread. As stated earlier, TVS diodes are a good addition, along with smaller breakers for each throttle.

I know the post war ZW has a 15 amp circuit breaker installed inside on the common side. Sounds like your ZW's breaker might be getting worn out but I doubt it, plus all the trains and lighted cars you are using put a large load on it.

Another option is to buy another ZW and use it for one of your three passenger trains. 3 or 4 engines powered plus at least 11 lighted passenger cars is a very large load for any post war ZW. Like gunrunnerjohn mentions a post war ZW may put out close to 220 usable watts to the track even though the power rating is 275 watts(used from the wall outlet).

What I have done is to install 7 amp 120 volt AC fast acting circuit breakers on each output terminal(A, B, C & D) between the transformer and the track. I bought these breakers at www.mouserelectronics.com  Personally I don't recommend using circuit breakers from automotive use as they are for use with DC(direct current) and you are using AC(alternating current). I studied electrical work for 3 years at a vo. tech. school near Reading PA, plus I studied automotive work at a vo. tech school in south Miami FL.

Lee Fritz

What wattage is a common incan lionel bulb in a passenger car?   Ive read 1.87, 2.80, and 4.80 watts.  I run a 6 car passenger train.  5 cars have 2 bulbs and 1(baggage) has one.  1986 Wabash 4-6-2.  And two DT&I diesel switchers that sound like grinders running (well used) double headed pulling 14 freight cars and a lit caboose.  With a single CW-80.  Sometimes for hours at a time.   12x6 layout with two outer mainlines right up to the edge.  On track that only has one power input on each loop.   Not yet bus wired.   Are the CW-80s that great or are the ZWs not that great?  

Edit.   I am currently adding another CW-80, not for more power but so I can control the two loops  independently.

carsntrains posted:

 Are the CW-80s that great or are the ZWs not that great? 

The original 50ish year old circuit breaker in the ZW seems to be bad and needs replacement. Once serviced, the ZW will run circles around the CW.

It should!   The new ZW cost well over 700.00...  Lists for 899.99 now.  You can buy 8 or 10 CW-80s for that.  I'm asking a serious question while considering moving up to a new ZW..  I like all the protections for electronics in the new transformers.   Don't want to go the brick route because I like to run conventional engines also. 

carsntrains posted:

It should!   The new ZW cost well over 700.00...  Lists for 899.99 now.  You can buy 8 or 10 CW-80s for that.  I'm asking a serious question while considering moving up to a new ZW..  I like all the protections for electronics in the new transformers.   Don't want to go the brick route because I like to run conventional engines also. 

We are talking about the only real original ZW in this thread which was under $30.00 new. The ZW-C, ZW-L are remotely related in styling only and completely different animals in terms of inner workings and components.

I really like that add!    Very cool!   Would love to buy some for 30.00 : )

Well, in 1954, $30 was real money, now it's just Chump Change.

$30 in 1954 is now $270 today.

Hey Phillyreading,  thanks for the info.  Found this in my research of AC vs DC breakers:

I run four trains on four loops on my layout but use two post war ZW transformers for power. Also use a 90 w transformer for lighting.  Never had a breaker blow except for a dead short.  If you wish to know if you keeping within the transformers specs measure the current  (in amps) that each train draws, then multiply that number by the running voltage (volts).  That gives you the wattage draw.,  If its 12 volts and 4 amps that's 48 watts and three trains = 144 watts. While a ZW is rated at 275 watts thats the transformer input draw wattage and not the wattage that it puts out. I would estimate that a ZW can deliver about 150 Watts on the output and at 12V on three transformer legs you are probably a bit over what that transformer can handle.

This has gotten WAY over complicated.

The attachment is the official Lionel position on transformer current capacities. Those values do not change with the setting of the throttle.

Circuit breakers respond to current flow in amperes. They don't know anything about watts. The rated wattage is the maximum drawn at full voltage and full current.

So, according to Lionel, a ZW will deliver 12 amps for at least 4 hours without tripping its breaker. It doesn't matter if it is 12 amps at 20 volts or 12 amps at 6 volts.

So if the ZW can deliver 12 amps of continuous operation, what is the amp rating of the internal circuit breaker?

Internal breaker is 15 Amps. Again, here are the three most common direct replacements available from most Postwar Lionel oriented Parts Suppliers:

Z22: 

ZW-232:

Modern Automotive Bussmann 19115 in a ZW-232 form-factor assembly: 

Drummer3 posted:

Hey Phillyreading,  thanks for the info.  Found this in my research of AC vs DC breakers:

Sorry, while this is technically true for reasons that don't really apply to your situation, it's mostly bullcrap.  The grain of truth in this clip is that a DC breaker will typically be rated lower than it's AC rating for the reason they stated, AC across the contacts is self-quenching at the zero crossing.  However, for thermal breakers, there's zero reason not to use an automotive DC breaker in your transformer.  Current is current as far as the thermal breaker is concerned, and 10 amps of RMS AC is the same as 10 amps of DC in terms of trip time.

Hi GRJ,

Advance Auto, my local auto parts store has this automatic reset breaker, but is 14-volts.  Would this be OK for a ZW?   Or do I need to look for a higher voltage rating?

If suitable, I will pick it  up tomorrow, and not have to mail order.

That breaker does not have any mounting or connecting hardware - you will need an additional socket like the BP/HHU pictured below. It has a mounting hole in the cap that may mount in the same place as the ZW-232. I would also stick to the stock 15 AMP rating for the breaker, but being a socket setup, you could easily swap out if you find it necessary. At these relatively toy voltages and currents, the 14V rating may slightly de-rate the breakers amperage rating at higher voltages, about 7.7 amps at 18V, but would be perfectly acceptable.

So Lionel says a ZW of any type can run 4 trains with no problems.   What baffles me is if they can.  Why are many here only running two trains per ZW??     How is that running circles around a CW-80 that I know will run 3 trains on one transformer for as long as you want them to run?   If it takes 2 ZWs to run 4 trains, or 5 ZWs  to run 10 trains, what advantage does it have over 4 or 5 CW80s running ONE train each? Or even 4 or 5 CW40s running 4 or 5 trains?   In 1954, 1923, or 2017 it just aint making sense to me??   Or that Z4000 or whatever it is.  Its description says it will only run two trains.   But I do understand the ZW and the other transformer do look cool.  I think any modern transformer is fine ..  and safe..  If you have good track wiring and keep your rails and equipment clean.   

To me.  the ZW is limited to two trains because it only has two large handles for control.  The other two small handles could ( theoretically ) be used to run two more trains but the two small handles are poorly placed and hard to get at easily,  so the small handles are better  used to just run accessories at a fixed voltage.

carsntrains posted:

So Lionel says a ZW of any type can run 4 trains with no problems.   What baffles me is if they can.  Why are many here only running two trains per ZW?? 

Those using ZWs are likely to be running in conventional mode with high current pullmor motors and incandescent lamps. A single train with dual motors and a long string of passenger cars full of lamps could easily pull almost triple digit watts. Additionally, while the ZW has 4 throttles, only 2 have whistle and direction controls, and thus the other two "throttles" are relegated to power some accessories.

How is that running circles around a CW-80 that I know will run 3 trains on one transformer for as long as you want them to run?   If it takes 2 ZWs to run 4 trains, or 5 ZWs  to run 10 trains, what advantage does it have over 4 or 5 CW80s running ONE train each? Or even 4 or 5 CW40s running 4 or 5 trains?   In 1954, 1923, or 2017 it just aint making sense to me??   Or that Z4000 or whatever it is.

Remember, transformers are rated on watts, not "how many trains" they run. A ZW is rated at 275 watts, the CW-80 only 80 watts. A CW-80 may be hard pressed to run that elegant dual pullmor motor loco with that long string of passenger cars. With modern can motors, command systems, and low power lighting, you could get away with using only one throttle set to 18V and have capacity to run 8 or more trains from a ZW.

 Its description says it will only run two trains.   But I do understand the ZW and the other transformer do look cool.  I think any modern transformer is fine ..  and safe..  If you have good track wiring and keep your rails and equipment clean.

You are entitled to power and maintain your empire how you will. Any properly serviced transformer of any age is safe.

This ZW thing has been kicked down the road for a long time. I have 2 ZWs, each one runs a conventional train.  I have a policy of not maxing out the equipment.  Things last longer  that way.