The case for fast-acting circuit protection

Circuit breakers protect the power source and downstream wires from burning up. They do not necessarily protect sensitive electronics. That is where a TVS Diode comes in to play.

Learn more: https://ogrforum.com/...uts-thoughts-on-this

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bmoran4 posted:

Circuit breakers protect the power source and downstream wires from burning up. They do not necessarily protect sensitive electronics. That is where a TVS Diode comes in to play.

Learn more: https://ogrforum.com/...uts-thoughts-on-this

https://ogrforum.com/...&queryString=TVS

To be more specific..a lot of thermal type circuit breakers have a slow rise time compared fast blow glass type fuses. I use 7.5 amp AGC fast blow glass type on each of my loops. They have served me well.

willygee posted:

bmoran4 posted:

Circuit breakers protect the power source and downstream wires from burning up. They do not necessarily protect sensitive electronics. That is where a TVS Diode comes in to play.

Learn more: https://ogrforum.com/...uts-thoughts-on-this

https://ogrforum.com/...&queryString=TVS

To be more specific..a lot of thermal type circuit breakers have a slow rise time compared fast blow glass type fuses. I use 7.5 amp AGC fast blow glass type on each of my loops. They have served me well.

How do you wire them up?

Gentlemen,

   This particular subject comes up quite a bit and for years I had a great small business that provided all the different Fast acting Resettable Breakers we needed for our hobby at a really reasonable cost.  

Unfortunately Scott's Odds and Ends sold out to Train Electric's LLC and the owner just recently closed the business.

I am going to try to find another small business that will supply these 5 thru 10 Amp Resettable Breakers for reasonable money.  

Seems the businesses who have them now are asking a great deal more money.

So far I have not been satisfied with the cost from the businesses who have the good breakers and none are making them up in Breaker Bank sets as Scott's and later Train Electric's did.

If and when I come up with another small business providing exactly what we need, I will let you know.

PCRR/Dave

Guess I should have purchased a few mores set of them from Scott's long ago.  I have 4 sets of the 10 Amper's however I donated the 7.5's to the Train Club Long ago.

Deuce,

   It's real simple you put the Quick acting Resettable Breaker on every Red line between your Transformer Channels and your Red inlet to your DCS TIU.  The Red outlet on the TIU is wired to the Center Rail of your layout.  This protects your TIU, because the older ZW, type Transformers have slow blowing fuses.  No need for additional TVS, because the DCS TIU has TVS built into it.  I even put them in front of my Z4K's, in this manner everything works perfectly.  The 7.5-10Amp Resettable Breakers or in line fuses are a must on all your older ZW & KW type transformers to safe guard your DCS and your expensive modern engines.

PCRR/Dave 

Deuce posted:

willygee posted:

bmoran4 posted:

Circuit breakers protect the power source and downstream wires from burning up. They do not necessarily protect sensitive electronics. That is where a TVS Diode comes in to play.

Learn more: https://ogrforum.com/...uts-thoughts-on-this

https://ogrforum.com/...&queryString=TVS

To be more specific..a lot of thermal type circuit breakers have a slow rise time compared fast blow glass type fuses. I use 7.5 amp AGC fast blow glass type on each of my loops. They have served me well.

How do you wire them up?

Inline fuses should be installed in series closest to the power source(transformer) to your track feed.

A picture from 2002.......if u look closely, u can see the in line fast action 10 amp fuses leading into the TIU.

Peter

Putnam Division posted:

A picture from 2002.......if u look closely, u can see the in line fast action 10 amp fuses leading into the TIU.

Peter

 

Wow..some serious power there like like PCRR/Dave...bet when you guys power up the neighborhood lights dim..

While  powering my 1992 built, 5 track, 15x32, twin shelf airborne operation with 3 pw ZWs I used fuses as protection. Later when I installed TMCC I replaced the ZWs with five 180 POHOs which have fast-acting breakers, added TVS diodes, and removed the fuse block.  The fuzzy photo below shows the fuse block and meter panel for the 5 power districts. The center "cartridge" is a piece of copper tubing on the Common circuit(white wire). The fuses were far better protection than the slow-acting {9-10 secs} $4 thermal Potter Brumfield breakers they replaced. 

Peter, I wanna know who left that big tip in the jar.

Dewey Trogdon posted:

While  powering my 1992 built, 5 track, 15x32, twin shelf airborne operation with 3 pw ZWs I used fuses as protection. Later when I installed TMCC I replaced the ZWs with five 180 POHOs which have fast-acting breakers, added TVS diodes, and removed the fuse block.  The fuzzy photo below shows the fuse block and meter panel for the 5 power districts. The center "cartridge" is a piece of copper tubing on the Common circuit(white wire)." The fuses were far better protection than the slow-acting {9-10 secs} $4 thermal Potter Brumfield breakers" they replaced. 

Couldn't agree more

I've always wondered why the manufacturers/importers didn't install TVS diodes on every modern engine to protect the boards.  Seems like a lower cost option than fulfilling warranties.

Also, the general consensus seems to be that with a modern transformer, no further TVS protection is needed at the track or within the engines themselves.  But with an older transformer, you must sprinkle TVS diodes throughout your layout - at the binding posts, at the lock-on, various places on the track, etc.  Would it be sufficient to only install TVS diodes at the binding post of an older transformer (with in-line fuse protection), similar to the modern transformer?

JD   TVS are needed with modern transformers as well as pw ZWs  and other older units. TVS are installed to arrest voltage spikes that can damage the locomotive's circuit boards and fragile wires.  Fuses and breakers are for overcurrent surges that can damage the transformer and possibly certain of the layouts railpower wiring runs.  A voltage spike will not trip the breaker or blow the fuse. High current does that, not voltage. You need TVS.

My take has been that the closer the TVS is to what it is protecting, the better. And I think that take came from Gunrunnerjohn. 

JD,

  If you are running DCS the TIU has TVS built right into the TIU, if you are not running DCS you definitely need to add TVS no matter what Transformer, old or new that you are using.  

PCRR/Dave

So does a guy with a MTH Z4000 and DCS TIU need additional TVS diodes sprinkled throughout the track system?  What if it is z4000 only with no tiu?

How about w a modern Lionel transformer cw80, gw180, zw-L - /legacy/Tmcc still need tvs diodes throughout the layout? What if only the transformer?

Sorry for basic questions, I'm a conventional runner only, but I'm interested in LC + and possibly command control In The future. 

Pine Creek Railroad posted:

JD,

  If you are running DCS the TIU has TVS built right into the TIU, if you are not running DCS you definitely need to add TVS no matter what Transformer, old or new that you are using.  

PCRR/Dave

Thanks Dave. You Answered my question as I was typing my last post. 

I guess this is where I'm confused.  So the TIU can control the voltage spikes before it ever gets to the track, but it's not enough to have TVS diodes only on the binding post of a PW ZW? 

Where/what is the source of the transient voltage spikes? Is it in the 120v in the wall, or can a transient voltage spike be created in the layout?

JD,

   Most use the binding post TVS method if they are not running DCS, and it works. Dewey is absolutely correct on this.  However the best place to have the TVS is actually in the engine itself, which no company that I know of, is providing.  Engineers like Bill (WilleyGee) and Techs like Guns or GGG and others probably have put them in some of their own Engines however.  I have been using the TIU for many many years and never had a problem.  Barry is correct about the TIU Engineering safeguarding just about everything.

All kinds of different reasons for the Spike's, lightening, accidents where a electric pole near your home is involved, ect.

PCRR/Dave

Gun Runner suggests that if you have an engine open for work it is a good time to install a TVS between hot and ground. [Hot is a wire to the center rail pickup, Common or ground to any suitable place on the chassis]. Failing that opportunity one can install TVS where railpower is connected at the track or at the transformer output. I long ago developed hand tremors and don't even consider opening an engine.  I installed my TVS at various railpower distribution terminal strips where a jumper runs from the strip up to the soldering point on the rail flange above. A master railpower distribution strip (2nd photo) that sorts out wire runs just after exiting the transformers out to separate power districts is a good place for TVS. Also, as noted above, on satellite terminal strips which have jumpers leading up to rail soldering.

Below:  Plate jumpered Satellite Terminal Strip equipped with TVS that provides protection for 5 potential railpower feeds. Green is Hot and code for the particular power district. White is Common. wires are from a 180 watt POHO transformer linked to a TPC [ track power controller].

Below:  Master Distribution Strip routing railpower from transformers to districts (TVS not installed in this 2010 photo)

Dewey,

   Could I install the TVS at the head of each one of my big MTH Terminal Blocks and cover every line connected to the Complete Terminal Block in this fashion you have shown.  Having additional TVS safety on every line connected to the big MTH Terminal Block or would this not really work?  I am an over kill type Engineer when it comes to safety & power on my layouts.

PCRR/Dave

Thanks for the great info Dave and Dewey. 

Seems like a no brainer that TVS should be installed stock on anything with a board. Job security for service teams?  They want to sell replacement boards?

John H posted:

Peter, I wanna know who left that big tip in the jar.

That's to help pay the electrical bill.

Dave

It would be redundant considering that the TIU already has TVS. But if you are like me with a belt, suspenders and elastic waistband mentality; I would install them on the MTH T- blocks. First off they are dirt cheap and second, in this case redundancy causes no harm. 

Pre knowledge of TVS  I had $85 Power Guards as spike protection.  I donated one to Dale Manquen (RIP) to do a "forensic" analysis and to compare its effectiveness to a TVS. Conclusion: the  $.50 TVS is far more effective than the $ 85 PowerGuard. The Point: I asked Dale if I should remove the redundancy of the PowerGuards and he said to leave them and enjoy their red/green indicator lights ( photo below).  

Dewey,

It's something I might consider after the Train Room Layouts are all completed, having the TIU on all my different track, I never even looked into the additional TVS at the head of each MTH terminal block.  I do remember long ago Guns and I had a discussion about adding them to some of the real expensive engines.  Having had absolutely no problems  because the TVS was in both my DCS TIU's, I let the TIU be my major safe guard thru out the layout.

PCRR/Dave

I put them on each of the two MTH twelve port blocks I have. I have 22 block feeds that hook to track drops at two position terminal strips, each with a TVS across the posts. All that advice came from here. 

Keep in mind an internal TIU tvs could be non functional(open and cannot be tested easily)...i removed mine and placed maintenance ones at the TIU outputs.

Dear WillyGee

Can you please provide the manufacture and part number for the "7.5 amp AGC fast blow glass type", please.

WillGee,

   So far the TVS in my TIU's have been doing the job, until I have a problem, which could happen, I will continue to depend on the TIU TVS's.  Your point is well taken however.

Bill I ordered the new connections for the DCS HHRC charging units, thanks for the info!

PCRR/Dave

nvocc5 posted:

Dear WillyGee

Can you please provide the manufacture and part number for the "7.5 amp AGC fast blow glass type", please.

Thank you!

while it is good it use tvs diodes for voltage spikes  ,be aware you can use them anywhere you want and as many as you want but when you get a shorted tvs diode the more you have installed the longer it will take to find for instance which one of the 30 tvs diodes you may have installed all over your layout and possibly if you installed them inside each engine! at least if its only in the engine you can try another engine on the same track and find out it was the other engine and not your layout!

not putting the tvs diodes down there great protection but when they fail shorted it will take time to find which one or how many went bad!

Alan 

Be somewhat careful adding too many TVS diodes, especially on a DCS layout.  The 1.5KE39CA 1500W commonly used TVS diode has around 1500pf of shunt capacitance.  At 3mhz, that 1500pf has a capacitive reactance of around 35 ohms.  Parallel enough of those and your DCS signal will be MIA.

All of the track feeds on my AC power source are protected by Polychem semiconductor current limiters. Never have had a problem.

Capacitance in series isn't a problem, it's capacitance across the power feeds that will attenuate the DCS signal.

gunrunnerjohn posted:

Be somewhat careful adding too many TVS diodes, especially on a DCS layout.  The 1.5KE39CA 1500W commonly used TVS diode has around 1500pf of shunt capacitance.  At 3mhz, that 1500pf has a capacitive reactance of around 35 ohms.  Parallel enough of those and your DCS signal will be MIA.

John, might the capacitance of a TVS diode be indicative of whether or not it is bad when it dies in the shorted mode? Most VOMs measure capacitance today.    Test and record the Capacitance. before installing.  After an event which you suspect may have stressed your TVS check the capacitance again.  My guess, the Capacitance will drop if the diode is shorted.             j

To be perfectly honest, I have no idea if the TVS is open that it might have less capacitance, but it does make sense that it likely would.  However, since you have to take it totally out of the circuit to test it, if I take one out, I just replace it.

When shorted, capacitance isn't a factor, a shorted component doesn't have measurable capacitance, it has infinite capacitance.

There is always the thread about the TVS tester that Stan came up with here.  GRJ and others designed some PCBs for them and some of the files for the PCBs are posted in the thread. As I recall there might have been a couple of different versions and sizes. The files can be uploaded to a PCB manufacturing site such as OSHPArk or JLCPCB and an order can easily be placed for some. 

I think I have a larger one I ended up with for myself that I don't think ever got posted. I decided a larger PCB with larger test pads might be nice to have so I made a bigger one. It's a bit easier to hold on to while testing as well. PCBs this size were rather pricey at OSHPArk as I recall, so I got mine from JLCPCB. They offer 5 PCBs, up to 100mm x 100mm for $2 plus $5 something for shipping, somewhere around $7.50 total for 5 of them. 

I don't think I ever posted the larger ones, but I'd have to check again to see what was actually posted there, it's been a while. Anyway, if anyone is interested I'd be happy to post the larger PCB files to the original thread I linked to above. 

Great info !!!

Thanks to all posters !!!

CB&Q Bill