I recently purchased a KW transformer. Dealer said it has new rollers, circuit breaker, and cord. The rollers and cord are easy enough to check, but how do I test the circuit breaker. Thanks.
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I have several ZW transformers. I have stocked up on 10 Amp auto fuses and pig-tailed fuse sockets, and connect an outboard fuse to each binding post of my ZWs. This will protect the modern digital stuff and eliminate any worries concerning 70 year old technology designed for PW Pullmor motors and mechanical E units.
Correction..... each "hot" binding post [A,B,C,&D] ... not the "U" binding post.
The breaker in my dad's ZW failed in an open state so it wouldn't send any power to any of the hot posts even with no load. I installed a modern 15 amp circuit breaker to replace the failed unit.
I guess if I wanted to test it, I could take a 20 amp automotive fuse and short one of the hot posts to a neutral to see what gives first, the 15 amp breaker or the 20 amp fuse. It's possible the fuse may still go first because the breaker will probable allow brief periods of current over he 15 amp rating.
Use modern electronic breakers on the outputs...
The PSX-AC units probable do good job but a $52 per unit that get's pricey real fast. Excellent protection can also be achieved with the combination of a good 8 amp breaker and a TVS at total cost of less than $5.
I already have external 5A circuit breakers I'll wire up ... but how do i test the internal breaker to see if it's good.
Inexpensive breakers are not fast enough. The electronics in an engine can cost $200.
To test the ZW, just put a short across the output, it should fault in about a second.
Deuce, from my earlier post:
I could take a 20 amp automotive fuse and short one of the hot posts to a neutral to see what gives first, the 15 amp breaker or the 20 amp fuse. It's possible the fuse may still go first because the breaker will probable allow brief periods of current over he 15 amp rating.
I'll add that if the 20 amp fuse pops too quickly you could try a 25 or 30 amp fuse and those should not pop against a 15 breaker. That breaker really should trip long before a 25 or 30 amp fuse. Yeah, this is pretty low tech method of testing a breaker.
The breaker in your transformer is most likely a thermal breaker and needs to build up heat before it will trip which is why they may allow more than 15 amps for a brief period before opening the circuit.
Deuce,
This is real simple, if you have a layout set up, simply short the mid track to one of the outside rails for a short time, when the voltage builds up the breaker will pop inside the KW Transformer. You must then remove the short and lower the handle to zero for a time. The old slow internal Breaker will then reset after a short time.
PCRR/Dave
Breakers don't protect the $200 electronics from a voltage spike, a TVS will. Even the fast acting breakers in the venerable Lionel PH180 bricks aren't fast enough to protect your electronics from a voltage spike.
PCRR/Dave's method works too! I guess I like to know how many amps the breaker takes before it opens.
No joke, I once saw a 50 amp auto-reset breaker installed in a ZW because that is all the person had at the time for an available replacement breaker.
Good grief, so many off-topic meandering posts about fuses, replacement options...Here is the direct answer to your question. It's quite simple:
1. Turn up throttle on KW
2. Stick a screwdriver across the terminals.
3. If the breaker pops within about 5 seconds, it's working.
Pine Creek Railroad posted:Deuce,
This is real simple, if you have a layout set up, simply short the mid track to one of the outside rails for a short time, when the voltage builds up the breaker will pop inside the KW Transformer. You must then remove the short and lower the handle to zero for a time. The old slow internal Breaker will then reset after a short time.
PCRR/Dave
Thanks Dave. Simple enough!
H1000 posted:Breakers don't protect the $200 electronics from a voltage spike, a TVS will. Even the fast acting breakers in the venerable Lionel PH180 bricks aren't fast enough to protect your electronics from a voltage spike.
Yeah, I've had that - fortunately - drilled into me. I have TVS's at every transformer post, at every terminal block, at every lockon for my O27 track, and under every fifth piece of FT. The only place I have not put them is inside my engines.
GregR posted:Good grief, so many off-topic meandering posts about fuses, replacement options...Here is the direct answer to your question. It's quite simple:
1. Turn up throttle on KW
2. Stick a screwdriver across the terminals.
3. If the breaker pops within about 5 seconds, it's working.
LOL. I think I can handle that. I understand the point of the fuses now that I have reread it. I don't intend on relying on the KW transformer to protect much (hence the 5A breakers and the TVS's) but it would really be nice to know it's still functional as a last resort to keep my table from bursting into flame.
GregR posted:Good grief, so many off-topic meandering posts about fuses, replacement options...Here is the direct answer to your question. It's quite simple:
1. Turn up throttle on KW
2. Stick a screwdriver across the terminals.
3. If the breaker pops within about 5 seconds, it's working.
I would also recommend at least disconnecting your layout first. If run anything with electronics, this method could send a voltage spike and zap them.
A controlled test of the circuit breaker is the best and safest way to check it out, not on your live layout. With fuses, now you know how many amps that breaker will pass before it opens, just in case someone someone decided to bypass the original breaker completely or install some insanely oversized 50 amp unit to replace the OEM unit.
I mean you could test a GFCI outlet by throwing a plugged in toaster into a bathtub full of water, but I'd rather just use the built in test button.
The Lionel specs. are as follows:
KW, full voltage with a 0.2 ohm resistor across the terminals, should trip with 20 amps in 15 to 45 seconds.
ZW, full voltage with a 0.1 ohm resistor across terminals, should trip with 30 amps in 11 to 40 seconds.
H1000 posted:Breakers don't protect the $200 electronics from a voltage spike, a TVS will. Even the fast acting breakers in the venerable Lionel PH180 bricks aren't fast enough to protect your electronics from a voltage spike.
Don't forget the TVS diodes - no matter how fast a circuit breaker is, it won't protect against transient voltages in the thousands of volts generated by the inductors all around your layout. See here for details: https://ogrforum.com/...80#72805549112847180
As for testing the internal breaker, wire A to U directly (nothing else wired in) and throttle about half way up. The breaker should pop within 10 seconds - yes - 10 seconds. Hence why it is recommended to have faster acting breakers as well.
Just remember, breaks/fuses protect against high current. TVS diodes protect against high voltages, especially those in the thousands of volts caused by EMF due to the various inductors all around the layout.
Amazing it took 4 people to give the simple answer, to Deuces simple question, without going overboard.
Teledoc, there are several facets that haven't been addressed.
The ZW internal breaker is thermal. The rate at which it heats up depends on the amperage. While a dead short may pop it fairly quickly (not really quickly enough), lesser overcurrents may take a long time.
To me, the specs David Johnston quoted above inadequate a grossly inadequate breaker. 30 amps for 39 seconds can cause damage to equipment. By comparison, the breaker in a PH-180 blows almost instantly, even upon a quick brush by a moving wheel flange against a switch center rail.
The statement was made above: "Correction..... each "hot" binding post [A,B,C,&D] ... not the "U" binding post." If each such breaker is 10 amps, you could have up to 40 amps flowing in the secondary winding, which really can't make more than 10 for longer periods. For adequate protection, one should put a breaker on each output post, and a 10-amp breaker on the U.
Note that the ZW internal breaker does not protect against a short between the A,B,C,D output posts, which can happen if they are at different settings and their outputs are shorted.
RJR, what I was referring to, were the replies that did not give a simple answer to his question. It is presumed, that it isn’t hooked up to anything. The simple test is plug it in, short “U” to A, B, C or D, and get the circuit breaker to trip. I agree that the “original” circuit breaker is thermal, and will take a little time to trip.
Then, secondarily, go through the other steps, that other posters have presented. There are some good responses, but totally skipped the Simple answer, on how to test. That’s all I replied to.
Deuce,
I answered your original question with my 1st post in your thread, it will test to make sure the old slow Breaker in your just acquired KW is functioning correctly.
This is not rocket science!
PCRR/Dave
PCRR, You were the first to give the “Simple” answer, which was the point I was making. Start with that answer, then make other recommendations after the fact, of the simple answer.
The classic example is someone posting an answer, like, I can’t help you, but your ...?... is really nice. Did that kind of response help the original poster...Of course not!!!
To me, the specs David Johnston quoted above inadequate a grossly inadequate breaker. 30 amps for 39 seconds can cause damage to equipment. By comparison, the breaker in a PH-180 blows almost instantly, even upon a quick brush by a moving wheel flange against a switch center rail.
The purpose of the internal circuit breakers in large Lionel transformers is to protect the transformer, not the trains. This is the reason many people recommend using external breakers. Postwar Lionel #91 adjustable electromagnetic breakers also trip instantly.
You are correct in your statement of intended purpose, C.W., but I question whether 30 amps flowing through the secondary of a ZW for 40 seconds will overheat it to the point of causing damage, like melting the insulating varnish.
I suspect that to get UL approval today, a transformer would also have to provide some measure of protection to the downstream circuits.
Teledoc, there are many persons turning to this forum who have little knowledge of a particular subject, and ask a question the answer to which has other ramifications. Thus, many responders go beyond the initial question. Deuce may or may not have realized that the fact a KW circuit breaker works or doesn't, really has little effect on the safety of his layout, that more protection is needed. It's another sign that forumites are willing to help others learn, which is a good thing, even though it may make for long threads.
I've performed the Lionel circuit breaker test numerous times on whatever transformer happened to be on my bench. I have yet to have a transformer damaged by the test.
Have you pulled 30 amps for 40 seconds?"
RJR posted:Teledoc, there are several facets that haven't been addressed.
The ZW internal breaker is thermal. The rate at which it heats up depends on the amperage. While a dead short may pop it fairly quickly (not really quickly enough), lesser overcurrents may take a long time.
To me, the specs David Johnston quoted above inadequate a grossly inadequate breaker. 30 amps for 39 seconds can cause damage to equipment. By comparison, the breaker in a PH-180 blows almost instantly, even upon a quick brush by a moving wheel flange against a switch center rail.
The statement was made above: "Correction..... each "hot" binding post [A,B,C,&D] ... not the "U" binding post." If each such breaker is 10 amps, you could have up to 40 amps flowing in the secondary winding, which really can't make more than 10 for longer periods. For adequate protection, one should put a breaker on each output post, and a 10-amp breaker on the U.
Note that the ZW internal breaker does not protect against a short between the A,B,C,D output posts, which can happen if they are at different settings and their outputs are shorted.
So did I read this correctly? Run the common line through a circuit breaker as well? So if I use the A and B posts, I'll need three breakers?
RJR posted:Have you pulled 30 amps for 40 seconds?"
Didn't take notes. Do you think Lionel would have published specs that would result in product damage?
I've never felt there was a need for an additional breaker on the common. I use postwar Lionel #91 adustable electromagnetic breakers.
Deuce, I actually don't use a breaker on the common, but I feel users should be aware of the possibility of overloading the transformer
C.W., Maybe. Years ago when in elementary school, I made a project using a hand-wound electromagnet, fed from my old type R. The breaker never opened, but when the transformer started smelling of hot rubber, I decided I'd better not use it.
bmoran4 posted:H1000 posted:Breakers don't protect the $200 electronics from a voltage spike, a TVS will. Even the fast acting breakers in the venerable Lionel PH180 bricks aren't fast enough to protect your electronics from a voltage spike.
Don't forget the TVS diodes - no matter how fast a circuit breaker is, it won't protect against transient voltages in the thousands of volts generated by the inductors all around your layout. See here for details: https://ogrforum.com/...80#72805549112847180
As for testing the internal breaker, wire A to U directly (nothing else wired in) and throttle about half way up. The breaker should pop within 10 seconds - yes - 10 seconds. Hence why it is recommended to have faster acting breakers as well.
Just remember, breaks/fuses protect against high current. TVS diodes protect against high voltages, especially those in the thousands of volts caused by EMF due to the various inductors all around the layout.
The PSX-AC
http://charlesro-com.3dcartsto...om/store_psx-ac.html
trips in milliseconds. As for the 10 second short before the conventional breaker trips, that is plenty of time for the wiring inside the engine (often pickup roller to pickup roller) to over heat and melt the whole bundle of wires it is running with. Shorts between those wires can take out boards, so it isn't just the transient voltage spike that can ruin $200 worth of boards. It's my experience that the PH-180 is fast as well. I use a post war ZW on the layout for lighting and accessories, but it has a PSX-AC on each of it's outputs. I use the ZW-C for the track voltages with the fast PH-180s.
In a direct short, these trip pretty fast, and Deuce already has some.
C.W., Maybe. Years ago when in elementary school, I made a project using a hand-wound electromagnet, fed from my old type R. The breaker never opened, but when the transformer started smelling of hot rubber, I decided I'd better not use it.
I could see that happening. Your project drew a lot of power, but not enough to trip the breaker. (or maybe your "R" had a bad breaker) An external breaker sized larger that your load would not have tripped either.
According to the Lionel charts, an R breaker should trip in 3-18 seconds supplying 18 amps across A-E or 16 Amps across B-E. I would have to figure out the load. The load would be the same as the KW load (.2 ohms quoted by David above).
No joke, I once saw a 50 amp auto-reset breaker installed in a ZW because that is all the person had at the time for an available replacement breaker.
Then there are those who would bypass the internal breaker, or make other "improvements". Any time a transformer is purchased, I think it should be gone over and tested by a knowledgeable person to ensure it is functioning correctly.
Plus, Postwar Lionel transformers were made at a time when things were made less foolproof, and people took responsibility for misuse.
Maybe it would really be best for people to only purchase recently made transformers that have all the protection built in.
I will stick with my "Z" and "ZW" transformers. I am confident in my ability to use them properly and notice when something is not working quite right.
cjack posted:The PSX-AC
http://charlesro-com.3dcartsto...om/store_psx-ac.html
trips in milliseconds. As for the 10 second short before the conventional breaker trips, that is plenty of time for the wiring inside the engine (often pickup roller to pickup roller) to over heat and melt the whole bundle of wires it is running with. Shorts between those wires can take out boards, so it isn't just the transient voltage spike that can ruin $200 worth of boards. It's my experience that the PH-180 is fast as well. I use a post war ZW on the layout for lighting and accessories, but it has a PSX-AC on each of it's outputs. I use the ZW-C for the track voltages with the fast PH-180s.
Yep I've seen the melted wires you are talking about. When you short two center rollers, that hot power wants to find the path of least resistance to the neutral power. That path is not necessarily going through your electronics, hence the melted wires. Things have to get pretty bad before the electronics start seeing the ill effects of a direct short via derailment. We're talking smoke and possibly flames bad. At this point, you've got bigger problems than a toasted $200 board.
No Doubt, the PSX-AC is well thought out and well engineered. however, at $52 per pop, that's a pricey solution that includes a lot features that will most likely go unused by the ordinary train "Joe".
Okay thermal breakers aren't fast enough for you. Try this magnetic breaker which opens within Milliseconds of reaching the current threshold. Add a TVS, and this solution is still under $12.
C.W., Interesting info on the Type R. I wonder why the difference in amps/time??? One other item about the R: there are several combinations of binding posts where there is no protection at all. I still have that old 1941 Type R that I got new back then, but now rarely use it as some of the insulation is getting ratty, and then only on the bench.
From your posts, I'm sure you do know how to use the Z & ZW, and they remain an excellent power supply.
H1000: The breaker to which you link is 15 amps. Personally, I prefer to use less. Unfortunately, there is a dearth of low-priced magnetic breakers, and as is pointed out, the PSX-AC is a bit pricey.
Maybe we could induce Gunrunner John to produce an electronic breaker kit. The other kits he produces are well though out and easy to assemble. Do you hear me, John?
RJR,
I'm sure smaller sizes are available. But when you think about, a ZW or KW will easily produce more than 15 amps in a short burst which would still trip this breaker in less than a second.
I'd take 15 amp surge for half second over a 10 amp surge dragged out over 10 to 30 seconds.
Somehow I think GRJ will note that some well engineered products like the PH180, PSX-AC, breakers, and TVS diodes have already been invented and he may be spinning his wheels to reinvent the wheel in this case. However, he has a wealth of knowledge and experience and a pleasant way of presenting valuable information. I would gladly welcome his thoughts on the subject!
H1000 posted:cjack posted:Okay thermal breakers aren't fast enough for you. Try this magnetic breaker which opens within Milliseconds of reaching the current threshold. Add a TVS, and this solution is still under $12.
H1000, I noticed the magnetic breaker you provided a link to, is rated 125VAC - 250VAC. Are you using this breaker? Do you know if it trips properly at lower voltages such as would be found on a conventional layout, say somewhere in the 8vac to 14vac range?
George
If you have one engine drawing 15 amps, that breaker won’t trip. Unless you have 12awg wire everywhere in the circuit, something will let out the magic smoke. I like to be just over my maximum normal amp draw with current protection. That’s why the 5 amp resettable works well for me.
George an amp is an amp, and its heating effect is the same, regardless of the voltage driving it through the breaker. Voltage rating becomes critical when you are trying to break high voltage circuits, where there will be arcing, or where the voltage is high enough to jump across insulation designed for low voltages.
