does the MTH Z1000 transformer's circuit breaker protect the PS2 board from damage in the event of a derailment. I'm currently using a Z4000 and I found out the hard way that it doesn't.
regards,
joe geiset
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No. The circuit breakers and overload protection of the transformers are there to protect the transformer and wiring, not the trains or their circuitry.
The damage to the electronics will be done before the breakers trip. This could instantaneous or cumulative.
There really isn't anything inherent in the design or function of an AC power supply that would provide such protection.
There are devices that have surge and/or transient protection to be used with transformers. QSI and K-Line made some, the Lionel Direct Connect lockon has protection, the MTH TIU has TVS protection.
Here are links to numerous discussions that will help guide you and assist with sourcing.
thanks Rob, I'll check it out.
regards,
joe
The individual circuit breakers (there are 4 of them) are there to protect the transformer.
However, the self-resetting circuit breaker that turns on the transformer's red light will protect the downstream electronics, including TIUs and engines, from a short circuit on the tracks.
Barry, thanks for the info. Are you referring to the Z 4000 or the Z 1000.
Regards,
Joe
Joe,
Barry, thanks for the info. Are you referring to the Z 4000 or the Z 1000.
The Z4000.
barry, in this instance it didn't work. tender uncoupled, derailed and was dragged, breaker never tripped. blew out audio chip, repairable but expensive. any thoughts?
regards,
joe
The breaker Barry describes "will protect the downstream electronics, including TIUs and engines, from a short circuit on the tracks", but will not protect on-board electronics from transient voltage spikes.
Although the TIU may have TVS protection, the TIU may not have been able to clamp the spike seen by the audio board. A TVS installed at the device is the most sure way of protecting it.
I install a TVS in each locomotive if I have them open for other work. IMO, the best place to protect the electronics is right at the device. I worked in avionics design for many years, and we were a big user of TVS devices on the inputs to the equipment.
Joe,
in this instance it didn't work. tender uncoupled, derailed and was dragged, breaker never tripped. blew out audio chip, repairable but expensive. any thoughts?
You didn't have a dead short, which is what a circuit breaker is designed to protect against.
What you had were continuing voltage spikes that, apparently:
- The TIU didn't clamp quickly enough
- That reached a level below what the TVS in the TIU would clamp and above what was needed to protect the audio amp, which could have been weakened by previous electrical damage
- The TVS could have been defective.
This should be a relatively rare occurrence, however, you just got "lucky". Sort of like a "perfect storm".
thanks guys, I should have mentioned that I was operating in conventional mode.
john, I like your idea of an on board TVS, what do you use and where can I get it?
regards,
joe
Joe,
I should have mentioned that I was operating in conventional mode.
Were you running through a TIU channel? If not, there wasn't any TVS spike protection at all.
barry,
no tiu, z4000 hooked up to the track directly.
regards,
joe
Originally Posted by joe geiser:
barry,
no tiu, z4000 hooked up to the track directly.
regards,
joe
Joe;
In this case you should definitely have a TVS wired across each of the Z-4000 outputs.
One that seems to work well is Mouser PN 1.5KE36CA.
It is only about 45 cents a piece, cheaper in larger quantities.
It can be wired across the Z-4000 outputs by using the component leads alone pushed through the holes in the Z-4000 binding post studs. Polarity does not matter.
They can also be installed in each engine if you wish by connecting between the center pickup roller wires and frame ground.
Rod
Rod,
thanks, exactly what I wanted to know, will order asap.
regards
joe geiser
rod,
is the TVS a one shot, or will it reset thanks.
regards,
joe
A TVS is a solid state zener diode clamping device. It does not trip or require resetting, it is completely transparent in operation and passive when not needed.
It's continuous, however you can overload them and then they'll fail. In this environment, I doubt you'll have transients that will kill them.
it never fails to amaze me, the wealth of information that exists on this forum and the readiness that most are willing to share it. Thanks again to all.
Regards,
Joe Geiser
Originally Posted by gunrunnerjohn:
It's continuous, however you can overload them and then they'll fail. In this environment, I doubt you'll have transients that will kill them.
I thought someone destroyed a TVS on another thread. At least it was the diagnosis of his problem.
You can cook them with a continuous over-voltage, as was said.
The PN I mentioned above has a 1500 watt rating.
A back EMF spike is a short thing; a small fraction of a second, and these are well able to handle them.
Rod
John, which TVS are you using in your engines?
Originally Posted by drodder:
John, which TVS are you using in your engines?
I use this one, the same one that Rod referenced.
Originally Posted by F&G RY:
I thought someone destroyed a TVS on another thread. At least it was the diagnosis of his problem.
They did, and it was due to putting 27+ volts on the TIU, and it cooked a 27 volt TVS. First off, the 27 volts exceeds the ratings of the TIU, so it's not surprising that something popped. Second, IMO, 27 volts is a tad low for the rating of the TVS, which is why I use the 36 volt ones. The transient spikes I'm worried about are the ones that are much higher voltage, but for very brief times, those are the ones that zap semiconductors.
No, but it will protect them from very high, damaging voltage spikes which can occur during a derailment and/or short circuit.
By definition, if there is a short circuit, the cruise commander and RS4 are shorted out of the circuit, so you can't really protect them from this(except to never have a derailment or short). However, when the circuit is rapidly closing(shorting) & opening like when wheels are dragging across the rails, this can result in transient voltage spikes.
How will you know if a TVS inside a loco has failed?
You wouldn't without an oscilloscope. But it would be very rare that you would have a 36 volt TVS failure, even if you tried to destroy it, in a model locomotive.
As Rob says, the TVS is there to clamp high voltage spikes, that's it's single mission in life. 
Gentlemen,
Got to tell ya I do not have a TVS and have never ever had a problem with a big time spike. Maybe some time I will regret not having the TVS but for almost 10 years I had my DCS layout running and never experienced a serious spike.
PCRR/Dave
Dave,
I do not have a TVS
Yes, you do. The TIU has TVS protection built-into each of its 4 channels.
Originally Posted by Pine Creek Railroad:
...never experienced a serious spike.
There is no way that you could know that. Unless you have recorded all operations with a scope on every circuit.
Barry,
That I did not know, so I am protected by the TIU engineering and did not even know it.
Rob,
The reason I know it, is I have no damaged equipment. If it has happened it was not big enough to cause any kind of damage. So to me I do not have a problem.
PCRR/Dave
Ever voltage spike doesn't kill things automatically. Many times it's the cumulative effect of many spikes that finally does the deed.
I've done many EMI/Lightning tests on avionics, and lots of times we'd be well into the test and something would croak because of inadequate transient protection. The circuits stood up to it for a time, but finally died. To be truthfully, I just watched the test, I was the engineer that designed it, and I was also the guy that got to fix it when it failed!
Originally Posted by Pine Creek Railroad:
The reason I know it, is I have no damaged equipment. If it has happened it was not big enough to cause any kind of damage.
This is a trap... there is no way you can know this either... the damage can be cumulative - akin to hypertension or hearing loss.
Originally Posted by Pine Creek Railroad:
Barry,
That I did not know, so I am protected by the TIU engineering and did not even know it.
Rob,
The reason I know it, is I have no damaged equipment. If it has happened it was not big enough to cause any kind of damage. So to me I do not have a problem.
PCRR/Dave
Maybe, just maybe, the dawn is breaking!
How many of you who have lived in your house for a few years without a serious fire would cancel your fire insurance and advise others to do so too? Well, welcome to this forum. You have company.
wolverine
Rob,
Your compairson does not wash, Hypertension and hearing loss are genetic,
however all electrical equipment wears as it is used. Sooner or later it needs repaired. Longevity failure is not what we are talking about, in this situation.
Immediate damage we can stop, longevity wear will always take place in every
electrical piece of gear.
wolverine,
Insurance and engineering are completely different, insurance is a bet that you make that something will happen, engineering is the discipline you use to control the outcome.
PCRR/Dave
My wording was poor, then. I didn't mean to refer to the root causes, only the effects.
The damage from hypertension is cumulative.
The damage from environmental noise exposure - any noise, is cumulative.
The damage from voltage spikes is cumulative. That's all we need to know for the purposes of preserving the electronics in the trains.
Originally Posted by Pine Creek Railroad:
...Longevity failure is not what we are talking about, in this situation.
Actually, it is what we are talking about. It's like the difference between carefully driving a car and caring for it through 300,000 miles, or beating the snot out of it so it's junk by the time it sees 60,000 miles.
Rob,
Your point is well made in that manner.
PCRR/Dave
Wonder why the manufactures don't put TVS protection in the trains themselves at least in the high end models the cost wouldn't seem to be an issue.
