When the smoke comes out...

I would bet the engines were  running  at different scale miles per hour and are slightly  fighting each other.   They can only fight each other so long and things begin to over heat .eventually they're fried.  

 I,m also a super mode runner(4 tiu)  5 tiu is the max for good operationsin my opinion., Some will say you can have more than 5 but on the other hand say having 2 tiu with the same number is a recipt for disaster.

We  use PW ZWs with 10 amp 32 volt fast blow glass fuses but have had "hot" lash-up problems, Fortunately we could smell the hot engines before they fried. 

There is NO way this can be happening!!

The best & brightest MTH minds on this forum all brag about HOW great DCS engines operate in a lashup!

The PS2 motor driver circuit via tach reader is the absolute best design in the world of model railroading...light years ahead of BEMF or RTC (Regulated Throttle Control)...That is until the speed dips below 3 smph then stutter stutter shake stutter 

CRH,

uh oh now you've done it!

oh boy wheres the popcorn

$oo

I mentioned in my post that we ran twelve lashups this weekend. That was a total of about 10 hours of run time.  Only one (1) of the lashups failed and so did one of the transformers powering that lashup.  Having run all sorts of lashups this is the first time I have ever experienced this.  My question still stands, is this a power related issue?

 come on CRH. You found a weak spot to pick on.

I guess I hadn't noticed this fighting as much with two rail as there's no tires. Now I'm getting more G gauge and noticing a lot more fighting. I've installed fuses to help protect the TIU. I think pairing the G gauge engines ( any with tires) up correctly helps prevent this.

 Why the Z failed??? What went first??? Wouldn't it have protected itself from overload? I'm interested in this as my bricks are Lionel. I'm switching them out to all MTH Z1000s to have all the same. I don't want to create power differences across blocks that the engines will have to carry?

I wonder exactly what inside the zw failed. 

and so when running 2 or 3 mu'ed engines at a time how do you know if there is a problem before it gets this far?

and why the fuses in the tiu didn't fail? am just curious is all.

$oo

Good questions.  We only connect to one throttle on the Z's.  When checking later we found that the other three (3) still work.  Havn't popped the top off yet to see what happened. 

I understand that late model TIU have a 20A fuse in them.  We were running 15A fuse between the Z and the TIU and it did not blow. 

digistew, wonder if the old roller material went bad that rolls across the windings for that particular handle?

a longgggggggggggggg time ago Jim Barrett did an old VCR Tape of the backshop showing how to replace them worth the money and still available from OGR would be a good idea to purchase it and watch it then see whats going on inside.

hey I just did a plug for the OGR store do I get a free bowl of popcorn Rich?

$oo

Yeah, that could be.  We'll find out soon enough when we open it up.  Hope you get your popcorn!  Thanks!!

 I don't want to create power differences across blocks that the engines will have to carry?

As mentioned above Joe may have the answer.  3 engines  crossing different power districts with the rollers straddling each zone. What if there's a short( or even no power) in the  zone ahead ?

Alex,

Each channel has a pair of Z's connected to share the load with 15A fuses between the Z and TIU channel.

You say each channel has a pair of Z's connected.

Only one transformer should be used to go through one channel of the TIU. Otherwise, you must use the TIU in passive where the transformers are connected directly to the track and the TIU just sends the DCS signal out to the track.

Running two Z's as such can run the amps up to 30 and be a cause for disaster for your engines even in passive mode.

While this is interesting, it is not part of the original thread. 

I wondered about this as well.  I think some had the theory that the Z

s were running hot and this would solve that problem.  That is somewhat true however, the actual problem was to much train (3 engines and 14 passenger cars pulling about 13 amps) and heating up the Z.  This past weekend we worked with an Amp meter to prove that point and the guys started pulling off the extra passenger cars until we can convert them to LED lighting.  Its an easy thing to do with a big layout and you want to run a long train.  I will pass along your suggestion. Btw, what is the maximum rated amperage per channel of a TIU?  Thanks!

Btw, what is the maximum rated amperage per channel of a TIU?

12 amps for each channel. Running a 10 amp fuse or circuit breaker between the ZW and TIU is a wise idea.

You can break the track into power districts using 2 or 3 transformers with a channel on each to spread out the load. This way only some of the train is running off each transformer.

It would be wise to also install an amp meter for each transformer/block. Since you run heavy loads.

Parallelling transformer can be an issue since they are not regulated.  You could have had one transformer trying to pull a larger share of the load, especially if the transformer voltages were different.  G

Excellent suggestion, I will encourage them to use these as well.  Sounds like a voltmeter would also be a good addition.  Or at least use a voltmeter to set the Throttle as the markings are not exact.  Thanks!

Being a newbie to this forum, I would like to express my appreciation to all of those that jumped in and offered their assistance.  I am very impressed and it shows how passionate folks are about this great hobby.  Thanks to everyone!!

I am interested to see the damage off the engine if a pic can be posted.  G

I'm running late. so what was the final conclusion, Tooo much train for the engines?

Question for GGG...Paralleling transformer , Not a good idea  but what kind of voltage would  it it be if the transformeres were out of phase, I'm susprised a TIU didn't get fried or did it?

Gregg,

Tooo much train for the engines?

I think too many amps available for the trains in my opinion. Even 20 amps can weld wheels to the track. Not good on electronics in engines.

Yes, two coupled Z's = approx. 30A with 15A fuse between Transformer(s) and TIU designed to handle 12A resulted in failed TIU Channel on one loop and failed engines on another.  BY the end of this weekends show we had three (3) toasted PS2 locos, two (2) failed TIU's and one crippled ZW.  Going forward I will be working with the layout owner to correct the problems from happening again.  Thanks again to everyone for their help!

 I believe it was Barry? who said that the only way to couple two bricks was with a TPC? (or something like?) for protection? I had abondoned the concept when I saw the welding capability of two bricks in arc mode (coupled).

 I have a Bridgewerks 20amp DC for more power now on the G scale and a 20 amp DC brick from Tank.

 Is DC current any safer?? 20amps DC=20amps AC. Hmmm. good thing I put smaller fuses inline?

 Try driving a train from a powered block onto a unpowered block (yard) with several engines parked on it. Scared the heck out of me.