What is a good circuit breaker when running new (digital ) and post war Lionel engines?
Thank-you,
Jack1943
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The answer depends on what you're using to power your layout. Please post the model numbers for your transformer(s) and any other power control devices you're using such as the Legacy Powermaster or TPC and which models. If you're also using MTH DCS, which units?
Other needed information would include how many independently wired track loops you have and how many locomotives you plan to run on each loop at the same time.
This information will provide a good starting point to answer your question.
Another useful data point is do you run strictly command, conventional, or a mixture of both?
Thanks for taking the time to identify what info is important for your response.
here is my input:
1. I run a home layout with 5 grandsons ,ages 5-15. They are careful but make mistakes.
2. I have 5 circuits I wish to protect
3.I use two Lionel ZWs and 1034 to power my layout.
4.I run MTH DCS with 1 TIU and 2 AIUs, using handheld MTH remotes or an iPad.
5. At maximum, we run 2 engines (post war Lionel)and/or MTH ps-2 (on an inner and outer loop) , and one post war trolley circuit. These are used most of the time. But I also have two circuits and two separate tracks that run off Momentary push buttons for fire car and a gang car.
Hope this helps and thanks for your thoughts.
Jack
I can say that agree with wanting to protect your trains from the potential damage that a stock ZW can do especially during derailments. In addition to breakers installed external to the PW ZW, also adding TVS diode protection would help.
275W PW ZW x 75% efficiency = 206 Watts output typical
206W/20V = 10.6 Amps nominal out
Since I don't have any experience with DCS, someone else would be better suited to making recommendations for that. To make the answer easier for that person, I'm including links to some possible so called "Instant Trip" options. Choosing the correct current rating and trip delay time are also important factors to consider.
Links to where to buy Airpax Snapac "Instant" trip Series Breakers
5 Amp
PP11-0-5.00A-OB-V
https://www.onlinecomponents.c...00aobv-10090638.html
7.5 Amp
PP11-0-7.50A-OC-V
https://www.onlinecomponents.c...50aocv-10090644.html
10 Amp
PP11-0-10.0A-OB-V
https://www.onlinecomponents.c...0aobv-10090622.html#
So if you went with a 10 amp and that overstated your power requirements, it wouldn't really protect your stuff from overload because the circuit wouldn't break until it reached past that point, right? Am I understanding this post correctly? I am asking because I'm wondering if I may need circuit breakers for my twin Z4000s as I run 5 PS3 engines at a time on a TIU using DCS.
@IRON HORSE posted:So if you went with a 10 amp and that overstated your power requirements, it wouldn't really protect your stuff from overload because the circuit wouldn't break until it reached past that point, right? Am I understanding this post correctly? I am asking because I'm wondering if I may need circuit breakers for my twin Z4000s as I run 5 PS3 engines at a time on a TIU using DCS.
Breaker sizing is to protect the secondary winding in the transformer, and that is all. Getting a good magnetic "instant" trip breaker is to remove current as quickly as possible after a short. This can help to reduce the chances something gets damaged by wild voltage swings when a derailed loco is shorting, then not, then shorting again during a derailment.
There is no silver bullet, but a TVS diode combined with a breaker like above or one of the PSX1 devices is your best bet to protect engines with sensitive electronics (and your TIU).
For the Z4000, I'm not positive, but I thought it had pretty good circuit breakers, someone else can comment on that part as I do not own one.
If a derailment happens where wheel/axle combinations short across the inside to outside rails, the PW ZW will definitely trip a 10A "instant" breaker. Not sure about the Z4000.
I use the PSX1 devices. They are the best defense to maybe save damage to your rolling stock and engines. Nothing is perfect, but these are the closest.
@rplst8 posted:Breaker sizing is to protect the secondary winding in the transformer, and that is all. Getting a good magnetic "instant" trip breaker is to remove current as quickly as possible after a short. This can help to reduce the chances something gets damaged by wild voltage swings when a derailed loco is shorting, then not, then shorting again during a derailment.
There is no silver bullet, but a TVS diode combined with a breaker like above or one of the PSX1 devices is your best bet to protect engines with sensitive electronics (and your TIU).
For the Z4000, I'm not positive, but I thought it had pretty good circuit breakers, someone else can comment on that part as I do not own one.
The only fast-acting breakers on the Z4K are 5he fixed voltage outputs. They trip instantly. The breakers for the track power outputs are very slow and I wouldn't rely on them to break an overloaded circuit. I was very surprised to learn this after I bought 2 brand new Z4Ks.
I was not awed by the breakers on the Z-4000, IMO the Lionel 180W bricks have a much better breaker.
Here is an older post discussing the Z4000 output capabilities that may be useful in choosing additional breaker protection.
This recent post discusses the "Instant" and other Airpax Snapac Hydraulic-Magnetic Circuit Breaker in more detail.
I "eavesdropped" on this conversation, since I need circuit breaker protection for track power provided by a MTH Z1000 to my modest size L-shaped layout. As I understand it, the circuit breaker built-in to the Z1000 isn't fast enough to protect the circuit boards in my MTH Aerotrain (with PS3) in event of a derailment. So I ordered the 10 amp circuit breaker cited in the thread.
Then I read that this circuit breaker is intended to protect the TRANSFORMER, not the circuitry in a locomotive. Maybe I wasted money on a 10 amp circuit breaker?
Mike Mottler LCCA 12394
mottlermike10@gmail.com
Mike, the breaker needs to be sized to be less than or equal to output of the transformer. As I understand it. the max rated output of the Z1000 is 100Watts. That would be a 5 Amp max breaker. A 10Amp breaker shouldn't ever trip on this transformer and would not offer additional protection. If you recently, placed your order you may still be able to call Online Components and cancel or change your order.
TVS diodes in combination with a very fast breaker will help protect the other electronics in a derailment.
@Mike H Mottler posted:I "eavesdropped" on this conversation, since I need circuit breaker protection for track power provided by a MTH Z1000 to my modest size L-shaped layout. As I understand it, the circuit breaker built-in to the Z1000 isn't fast enough to protect the circuit boards in my MTH Aerotrain (with PS3) in event of a derailment. So I ordered the 10 amp circuit breaker cited in the thread.
Then I read that this circuit breaker is intended to protect the TRANSFORMER, not the circuitry in a locomotive. Maybe I wasted money on a 10 amp circuit breaker?
In addition to what SteveH said, let me explain in a little more detail. There are really two overcurrent failure modes that we’re looking to solve here. One is protection of the transformer windings. This is a slow, time vs. heat dissipation problem.
The transformer is made from copper wire and all wire has a current carrying capacity. When the rated current of a piece of wire is exceeded, it doesn’t instantaneously explode, or even melt. It begins to heat up on a sliding scale. Eventually, yes it could melt, or catch fire, but pulling 7.1A through a wire rated for 7A does not spell doom. However, in a transformer the wire does not have any insulation, just a coating of varnish. If that melts, it will short the winding and then a LOT of current can flow totally destroying the transformer.
Ideally we want a breaker that will allow us to pull the rated output power of the transformer without nuisance trips, yet save us when we try to put one too many lighted cars on the tracks.
Generally speaking many, if not most, manufacturers “cheat” by using thermal breakers and downsizing them so protect the transformer. This works because thermal breakers have a natural trip curve where at 1x rated capacity it might take 2 hours to trip. At 2x capacity it might trip in 1 min. Who runs their transformers near max capacity for 2 hours straight? Not many I’d wager.
The second overcurrent failure mode is a short circuit. Here, because the resistance is near zero, A LOT of current will flow quickly. This will typically heat up a thermal breaker very fast and cause it to trip in seconds. However during a derailment, contact is often on again off again on again possibly not long enough to heat a thermal breaker or trip a “slow” magnetic one. While this is going on, each short, open, short, spark, etc. is causing wild voltage swings. It’s these high voltages that can damage electronics.
It is for this reason many of us have become interested in “instant” magnetic breakers. They trip so fast that once the first short happens, the circuit is disconnected, reducing the time, and therefore probability of damage. Combined with TVS diodes, this is a layered protection strategy to help prevent damage from accidents on the rails.
@rplst8 Ryan, thank you for taking the time to write an excellent explanation of the issues we're trying to address with the instant breakers and TVS diodes working in combination to prevent damage to our train's electronics. My hasty reply just before dinner was in the hope that @Mike H Mottler might still be able call to change or cancel his order before Online Components in Arizona closed today.
To anyone considering the purchase of one of these "instant" trip breakers, if you are unsure of which particular model to choose, I'm sure someone here in the Electrical Forum would be happy to offer guidance on the right one(s) based on your individual circumstances (transformer and number and types of locomotives and cars you typically run on your layout).
Steve H.
Thanks for your follow-up comment. With a good intention, I placed the order for the circuit breaker. But I cancelled it with the hope that I'm not too late to avoid a misguided purchase.
Meanwhile, I'm considering a second Lionel "trackside cabinet" accessory that is a fast-acting circuit breaker for my layout. I already have one in the track power circuit fed by a Lionel Powerhouse "brick." I need another one for the track power circuit fed by a MTH Z1000.
Mike Mottler LCCA 12394
mottlermike10@gmail.com
I believe the The Lionel TMCC Direct Lockon SKU: 6-34120 (135W setting) breaker's trip current would a bit too high to provide adequate protection with the Z-1000.
There are a few electrical fundamentals in addition to the trip delay time one should understand when choosing a breaker. The transformer Output ratings are a good place to start. Here's what they mean:
Volts - (electrical energy potential) in Conventional operation this sets the train speed.
Amps (current flow) - More Locos, cars and such (and shorts) pull more current through the circuit from the transformer. The transformer only delivers as much current as required by the load, up to a point. This point is it's Output rating.
AC Transformer Output ratings are usually given in either Watts or VoltAmps, both of which have essentially the same meaning when choosing breaker size.
Watts = Volts x Amps = VA or Watts/Volts = Amps
From the MTH website: Z-1000 Owner's Manual
It shows a 6Amp breaker inside the transformer housing. This is presumably a thermal (slower) breaker designed to protect the transformer from overload.
Output: 14VAC 80W
18VAC 100W
Current at 18V = 5.56 Amps, or at 14V = 5.7 Amps
Given all this information, if you are interested in providing faster protection than the Z-1000 internal 6A thermal breaker, I believe the 5A Airpax Instant might be a good choice for you, especially if you also add TVS protection are recommended.
PP11-0-5.00A-OB-V https://www.onlinecomponents.c...00aobv-10090638.html
I hope this helps.
The two biggest issues I have with the TMCC Direct Lockon.
One, it hammers the load with reconnecting the power repeatedly once an overload is protected.
Two, it kills the DCS signal, so you need to put it before your TIU if you run DCS.
@gunrunnerjohn EDIT: how does the TMCC Direct Lockon sense and disconnect an overload?
The TMCC Direct Lockon has an electronic circuit with a relay to interrupt the current. I just don't like transformers or other circuit protection that restores power before I get a chance to correct whatever caused the trip in the first place.
@gunrunnerjohn Agreed that a manual breaker reset is preferable.
Do you know of any information available on the TMCC Direct Lockon's delay curve or do you have have any thoughts about how it compares to the 0.1 second delay time of the Airpax "Instant" (manual reset) breaker.
I never spend any time characterizing the TMCC DL, I may even still have one somewhere in a box here... 
@gunrunnerjohn if you can find the time and the TMCC DL, this sounds like it could be a good opportunity to demonstrate some of the capabilities or your new toy.... oh I meant to say professional grade 16ch digital storage oscilloscope. 
Truthfully Steve, I have enough projects that I can demonstrate my new toys, I don't need to invent them! 
Steve H.
Thanks for the add'l info. I was too late to cancel my initial order for a 10 amp circuit breaker, so I place another order for the 5 amp version. What is a TVS and where can I order one? I'll add that to the circuit.
GRJ:
I'll rely on the 5A circuit breaker and TVS for circuit protection; not the Lionel direct lock-on based on your comment.
With appreciation,
Mike Mottler LCCA 12394
mottlermike10@gmail.com
mott
Mike I'd suggest more than one TVS diode. To read more about them and where to install, this recent Thread has some helpful info.
TVS and Fast Acting Circuit Breaker help
You can get them in qty. 10 or more for less than 60 cents each plus shipping. Here's a link
Steve,
Would the 10 amp breaker you mentioned above be good for a z4000?
@Casper I'm not very familiar with the Z4000 and before you buy breakers, maybe someone who is could confirm. According to a quick look at the Z4000 Manual, it's track outputs are 180W each.
I think one 10Amp Airpax Snapac "instant" breaker on each variable track output may be a good match with the Z4000, but not on it's Aux outputs. I believe the Aux outputs may be rated for less wattage.
Steve H.
Today I placed an order online for 10 TVS devices. More than I need, but they're cheap; I'll have extras in event of burn-outs. I intend to place them on my L-shaped layout in the track power circuit between the MTH Z1000 transformer output and the MTH Remote Commander receiver.
OR ... should the TVS be installed after the MTH Remote Commander and the track lock-on? I'm a novice at this device ...
With appreciation,
Mike Mottler LCCA 12394
mottlermike10@gmail.com
Don't go crazy with TVS devices, they have the potential to impact the DCS track signal. Also, under normal circumstances, a TVS diode will last many years. You shouldn't have more than a couple on any one power district.
If you're using the DCS Remote Commander, it doesn't have that strong a signal in the best of times, so don't do too much to weaken it.
Edit: I see GRJ beat me to this, but maybe this is still helpful.
Mike, I'm also somewhat of a novice with TVS diodes, but I've been studying it and reading the advice of others with more experience and an in depth understanding of Transient Voltage propagation. I'm especially a novice when it comes to working with DCS control and wiring.
What I think I understand correctly from what others more knowledgeable than me have written (and makes sense) is that the closer the TVS diodes are to what they're intended to protect the better they protect it. The ideal place would be in the trains right next to their sensitive electronics, wired directly across the incoming power wires at the circuit board end. Additional places throughout the track circuits improve this protection.
Personally, I'm not sure I want to install TVS diodes in every locomotive, because of what would be involved. I'm considering installing my TVS diodes at every power drop at the track end, adjacent to the track and maybe (or maybe not) in certain locos. There is some risk by not installing the TVS diodes in the locos because of the way the high frequency transient electrical waves created by derailments "bounce" back and forth along all conductors attached to the track.
Put another way, as I understand the principle, even though a TVS diode may be clamping the voltage to a safe level at the exact spot where it's connected, inches away the voltage can oscillate substantially higher for brief periods of time until after the "instant" breaker removes the current driving this wave and the TVS diodes working in concert can sufficiently attenuate this "bouncing" voltage wave. Maybe this isn't a 100% technically correct way of explaining the transient wave propagation, but I hope it at least gives you a better idea of what we're trying to deal with.
If I've made a misstatement, or if application of TVS diodes in a DCS environment would differ, someone else please enlighten us.
The major issue with too much of a good thing regarding the TVS diodes is the stray capacitance they exhibit. The typically recommended 1500W TVS has over 1nf of capacitance! At the mean DCS carrier frequency of 3.27mhz, that's like putting a 50 ohm resistor across the DCS signal! Do that with half a dozen TVS diodes and you don't have any DCS signal!
@Mike H Mottler posted:Steve H.
Thanks for the add'l info. I was too late to cancel my initial order for a 10 amp circuit breaker, so I place another order for the 5 amp version.
Your extra 10A breaker may not be a waste. Combined in series with a typical thermal breaker, it should still provide fast acting short circuit protection. I haven’t measured to see, but I’d wager the Snapac would beat any thermal breaker during a short on transformers that can normally supply 5 or more amps.
GRJ:
Steve H:
Thanks for the electro-psycho-emotional support as I wander into (for me) new territory with a circuit breaker and a TVS!
GRJ:
Also, on Saturday my layout helper and I will tackle the geometry problem that limits my MTH Aerotrain from getting around an O42 curve because the Elevated Trestle supports for the upper level (located right above this curve) are set too close to the rails of the lower level where the Aerotrain is running. Meanwhile, there are two other locations on my L-shaped layout where similar geometry problems lurk.
We'll remove as many supports that block the path of the loco at the curves. I may have to re-install supports (with a smaller profile) to provide adequate support to the upper level -- where three trolley lines and 35 DEPT 56 lighted porcelain buildings are placed.
I feel like the guy who built a boat in the basement and when finished discovered the craft wouldn't fit through the cellar door to the outside.
Mike Mottler LCCA 12394
Obviously, not an honor student in HS Geometry Class
mottlermike10@gmail.com
@Casper does your Z4000 list the output rating on the back panel for the Aux outputs? If so, would you please post that info? Maybe a pic would be even better.
