Mount them in a foam box. 
John,
You mentioned conventional operation. Does that mean you are using the Z-Controller with the Z1000? The Z-Controller converts the Z1000 sine wave output into a chopped waveform for voltages lower than 18 VAC. I haven't tested the Airpax with the Z-Controller but I suspect that might be the cause for your buzzing.
@Bruce Brown posted:John,
You mentioned conventional operation. Does that mean you are using the Z-Controller with the Z1000? The Z-Controller converts the Z1000 sine wave output into a chopped waveform for voltages lower than 18 VAC. I haven't tested the Airpax with the Z-Controller but I suspect that might be the cause for your buzzing.
Short answer - Yes.
John - Foam box - check 
John,
The Z1000 already has a built-in thermal breaker that works just fine. If you want additional protection an inexpensive thermal breaker like the P&B W28-XQ1A-5, recommended in Jim Barrett's OGR video, will "pop" in 1.5 to 2 seconds in a short. The transformer will be well protected. Using fuses is a nuisance.
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@Bruce Brown posted:John,
The Z1000 already has a built-in thermal breaker that works just fine. If you want additional protection an inexpensive thermal breaker like the P&B W28-XQ1A-5, recommended in Jim Barrett's OGR video, will "pop" in 1.5 to 2 seconds in a short. The transformer will be well protected. Using fuses is a nuisance.
Isn't there a thermal breaker already on it? I thought the magnetic breaker was the answer to the delayed action of the Z1000 thermal breaker that takes too long to trip?
I'm Confused.
John
There is a very similar thermal breaker in it, and we all know that one isn't all that fast. AAMOF, I believe that MTH uses the same style breaker!
Also, that P&B breaker isn't quite as fast as Bruce is representing without a lot of current, likely more than the Z-1000 would supply. Let's consult the data sheet.
---Click on graphic to expand---
As you can see, at 135% of the rated power, it takes up to an hour for the breaker to trip. For 200% of the rated current, it can take up to 15 seconds. I don't think there's any doubt that the Airpax zero delay magnetic breaker provides much better protection.
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John,
Yes. The Z1000 has a thermal breaker. In bench tests when putting the P&B W28 breaker inline with the Z1000 and creating a dead short, the P&B W28 pops before the internal Z1000 breaker does. At 18 VAC, with a dead short, breakers open immediately. The 1 to 2 seconds delay I mentioned above is when lower track voltages, like 10 VAC, are used for conventional operation. The W28 will also react faster than the internal breakers on the Z4000.
If you wade through the many OGR threads on breakers, there is a wide difference of opinion on the value and purpose of breakers. Most people agree that their purpose is to protect the transformer and to reduce heating effects at the point of the short. But it is far less certain if a breaker actually plays any role in protecting electronics, say, in an engine. The use of the TVS voltage clamper may be more valuable for that purpose.
The Airpax/Sensata is an instant breaker. It will react instantly on any type of short. I use it for the Acela Set where I want the engines to immediately shut down in a derailment so as not to put a drag on their motors. The negative part of these breakers is that they can be a nuisance running certain types of engines through switches where there might be a momentary, almost imperceptible, short. I had to put a bypass switch on the Airpax/Sensata breaker when running most of my other engines.
It is safe to say that an external breaker should be used with the post-war transformers, like the ZW, where their internal breaker may be suspect.
Many folks have reported that the 20A fuses in the TIU go before the 6A circuit breaker on the Z1000 brick, in my mind that makes them in adequate. I used a Z1000 on my bench for several years, but I was always unhappy with the circuit breaker response. I now have a switchable 2A breaker for most work on the bench, I only switch it out if I'm working on something like an old Pulmore powered locomotive.
When I'm not sure the 2A breaker will be sufficient, I have the old Lionel PW #91 magnetic breaker, it has never failed to trip instantly on any short. Also, that 2A breaker has never tripped before the #91, even when I'm using the high current side of the #91 breaker.
You'll get no argument about PW transformers, I wouldn't use any of them without a better circuit protection scheme in front of the transformer.
I’ve been using the Z-Controller and Z-1000 transformer for 15 years without any add-on breakers or fuses. Can’t tell you how many times that I‘ve popped the breaker in this system. I’ve never had any damage done to the transformer or any electronics in any engine.
First, the thing that everyone should realize is that the “brick” portion of the cheap “Z” transformers from MTH (Z-500, Z-750, Z-1000) are just transformers with two taps and a breaker. That’s it.
The Z-Controller portion is what does the “chopped sine wave” part.
Many of us with MTH TIUs use the brick part only to power the layout through the TIU. Others use Lionels PowerHouse 180s or 135s. The Lionel GW180 similarly can be used, just chuck the controller part and use only the brick.
Second, the Airpax instant breakers come in a few varieties. There are versions for DC, 50/60Hz power, 400Hz (aircraft), and maybe a few others.
Third, using these breakers with a “chopped sine wave” controller is a crap shoot. Whatever funky transform and phase changes these controllers impart on the AC waveform will cease to make this “50/60Hz” power. Expecting the breaker to work here is a recipe for failure.
Fourth, circuit breakers don’t inherently, protect electronics. When I first started looking into these it was after Adrian’s post about the variable frequency products that happen during a derailment, and how TVS diodes only work correctly if they are less than some fraction of a wavelength from the device to protect. And that the ill effects of shorts and derailments can be cumulative overtime. Then after someone, I think GRJ, mentioned that the PH180 used a really fast breaker, I started to research “really fast breakers” thinking that a fast acting breaker would shorten the duration of a short, and lessen the damage done to sensitive electronics.
Since it’s a good idea to add a modern circuit breaker to our post-war transformers anyway, why not use one that might afford us some prevention of damage by reducing the time these variable frequency and wild transients happen during a layout disaster.
P.S. By suggesting their use, I never intended them to replace properly installed TVS devices.
@rplst8 posted:Since it’s a good idea to add a modern circuit breaker to our post-war transformers anyway, why not use one that might afford us some prevention of damage by reducing the time these variable frequency and wild transients happen during a layout disaster.
Very good idea, and thanks for the clarification.
But now, specifically, which one would that be?
Mike
IMO, the faster you interrupt power when you have a short of any kind, the better. If you leave power on too long, you get something that looks like this!
Yes, I'm pretty sure that a swift removal of power would have minimized the damage to this Cruise Commander and I could have replaced the offending FET for a few dollars and saved a $150 board.
Disclaimer: This came from a customer and I don't know what circuit protection he has, but he mentioned smoke curling out of the locomotive before he removed the power, but I'm guessing it is isn't a really fast circuit breaker!
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So if the chopped waveform output of the Z-Controller is hypothetically causing the Airpax Instant breakers to buzz well below their trip current rating and the Z-1000 brick is outputting a pure sine wave, how about this?
Make an adapter cable so that the Airpax Instant breaker can be connected between the Z-1000 output and the Z-Controller input...
@SteveH posted:So if the chopped waveform output of the Z-Controller is hypothetically causing the Airpax Instant breakers to buzz well below their current rating and the Z-1000 brick is outputting a pure sine wave, how about this?
Make an adapter cable so that the breaker can be connected between the Z-1000 output and the Z-Controller input...
Boom. Not all heroes wear capes.
@gunrunnerjohn posted:
... he mentioned smoke curling out of the locomotive before he removed the power, but I'm guessing it is isn't a really fast circuit breaker!
I thought our locomotives were supposed to smoke? 
@Mellow Hudson Mike posted:Very good idea, and thanks for the clarification.
But now, specifically, which one would that be?
Mike
The ones that are the topic of the thread.
@SteveH posted:So if the chopped waveform output of the Z-Controller is hypothetically causing the Airpax Instant breakers to buzz well below their trip current rating and the Z-1000 brick is outputting a pure sine wave, how about this?
Make an adapter cable so that the Airpax Instant breaker can be connected between the Z-1000 output and the Z-Controller input...
Nope.
@rplst8 posted:The ones that are the topic of the thread.
Ok. That's what I thought. Just wanted to clarify.
Thanks.
Mike
@PLCProf posted:Nope.
I'm not understanding why this is a bad idea. 
@gunrunnerjohn posted:I'm not understanding why this is a bad idea.
Because, by definition, the current is the same throughout a series circuit. The Z1000 controller, just like the CW-80 and others, has a triac in series with one of the power leads. So, while the voltage waveform going into the controller is a sine wave, the current waveform is identical to that at the output.
Exactly the same principle as a light switch. The current on both sides of the switch is identical, whether the switch is on or off. The voltage, however, depends on the position of the switch!
Just a quick P.S, because the circuit breaker is wired in series with the load, all it knows about is the circuit current, not the supply voltage (until the breaker opens, anyway.)
An excellent point, thanks for the slap to get my mind right!
@PLCProf posted:Because, by definition, the current is the same throughout a series circuit.
If a sufficiently sized inductor were to be added in series between the breaker output and the Controller input, would this smooth out the current enough to prevent the breaker from buzzing while operating within it's nominal current range?
@Mellow Hudson Mike posted:Ok. That's what I thought. Just wanted to clarify.
Thanks.
Mike
These are also a candidate, though I have not tested them myself … https://www.carlingtech.com/si...s_%26_COS_030314.pdf
@SteveH posted:If a sufficiently sized inductor were to be added in series between the breaker output and the Controller input, would this smooth out the current enough to prevent the breaker from buzzing while operating within it's nominal current range?
If you wanted to you could engineer something like that, but bear in mind that a rapid current change through an inductance (like sparking due to a derailment) is the source of the voltage spikes you are worried about in the first place!
True, although there are no shortage of coils on a layout already: transformer, uncouplers, solenoids, relays and such. Assuming adequate TVS protections, would another inductive source make much difference?
Just speaking in terms of a ballpark estimation, what value of inductor might it take to smooth out the current in this specific application?
The other problem with a series inductor is it adds impedance and also shifts the power factor, neither are necessarily desirable outcomes.
PLC Prof and GRJ , thank you for the indulgence and reminders on Power Factor. Sorry to Craftech and others that my proposal isn't feasible.
I picked up some 5A Airpax instant-trip breakers and have one in series for my track power from my K-Line Power Chief transformer, which has a chopped sine wave like the CW-80. When my new-to-me Williams FA-1 arrived I noticed the circuit breaker buzzing, especially when I used the horn and bell buttons. With two dummy locomotives and 5-6 scale freight cars and a caboose the circuit breaker would trip at ~75% full throttle. Wiring the Williams FA-1 in series reduced the buzzing significantly.
I tried my other diesels and they all cause the circuit breaker to buzz, some more than others. It turns out I had been running mostly LionChieft/LionCheif plus steamers and they apparently require less power than the two-engine diesels and don't cause the circuit breaker to buzz, as far as I can tell.
I switched to a WBB 80-watt transformer, which has a pure sine wave, and the buzzing ceased.
Question: do I replace the 5A Airpax breaker with an 8A Airpax instant-trip breaker or do I get a pure sine wave transformer such as an American Flyer 16B (7-18V) and stick with the 5A breaker?
@Matt_GNo27 posted:
Question: do I replace the 5A Airpax breaker with an 8A Airpax instant-trip breaker or do I get a pure sine wave transformer such as an American Flyer 16B (7-18V) and stick with the 5A breaker?
Even when I used a pure sine wave transformer, the 5A Airpax would buzz. I switched to the 7.5A version and the problem went away.
@Matt_GNo27 posted:........................ Wiring the Williams FA-1 reduced the buzzing significantly...............
Do you mean wiring it in series?
John
@Craftech posted:Do you mean wiring it in series?John
Yes. Fixed it. Thank you for catching that.
I ordered some 8A Airpax / Sensata breakers (PR11-0-8.00A-XX-V) and they arrived today. Since only a couple of my locomotives cause the 5A breaker to buzz, instead of swapping out the 5A for an 8A, I added a STDT, on-off-on toggle switch, so that I can switch between the 5A and 8A breakers depending on the current load of the the train I'm running. Using 8A breaker eliminates the buzzing for the offending locomotives. (The toggle is in the off position in the photo. Since the photo was taken, I've written an "8" on the white push-to-reset button with a fine-point sharpie.)
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