Useing an old lionl transformer with new circit bord locomotives

Hey milwaukeerr radioshack has inline fuse holders.. Dont use anything biger than a 10amp fuse.

for your 1033, I'd use no more than a 5 amp fuse, preferably a 4 amp. since you are only using a single train under the tree that should be enough. I'd also get automotive(ATC) type fuses, as they are rated at low volts(32 vs. 125). inline fuse holders are available for ATC style fuses. I'd get them(fuses and holder) at any autoparts store, as the selection of fuses is likely larger that Radioshacks. 

I agree both that a 5 amp fuse is what you want, and that the autoparts store is best.  Just buy a littlefuse type in -line holder that will just slip right into the lead from the transformer to the track.  Then buy several 5 amp fuses (well, buy plenty, accidents happen and you would not want to be without a fuse come Christmas morning).

Is any one familiar with Transient Voltage Suppressors? Its a surge protector basically. I read people are using these with the in line fuses as well. It protects against surges something the fuse will not help with.

 Do a search on it here in the forum. There was a LOT of discussion on it...

The Transient Voltage Supressor [TVS] protects against "Voltage Spikes" emerging from the transformer that can damage fragile electronics in Locomotive circuit boards.

Circuit breakers protect the transformer itself from overcurrent surges and do not trip  from Voltage Spikes thus the need for TVS.  Both are necessary for good protection and are relative inexpensive. A TVS is only 40-50 cents and is easy to wire across the line. A breaker or fuses are wired inline. A TVS shown below which was connected between the A and U posts on a pw ZW. Connected across the line like a short but doesn't . At Mouser Electronics it is part #625-1.SKE36Ca. Order a dozen.

These are correct, but just get a new transformer.

No, you wire it between the Hot and Common on the wire run to every power district.

I know it seems like a "short" but the TVS does not create one. The circuit breaker is wired inline on the hot wire run but the TVS is wired across the line as noted by the example I mentioned --between the A and U  posts on a pw ZW.

Whether the transformer is old or new a TVS is good protection of your engine's electronic circuits. The MTH TIU has TVS built in but transformers do not, nor do engines.

OKay,....why doesn't Every piece has protection in it?

Check the auto parts stores such as Autozone for a resettable automobile type breaker in the 4-5 amp range. But, as Lee suggested above, for your single train Christmas running round the tree a simple solution is an inline cartridge fuseholder and spare 5 amp fuses. All found at the auto stores--NAPA, Autozone, etc.

Since you are just running one train under the tree 4-5 amp rating is plenty large for protection. Aside from auto stores your choices for breakers are Mouser Electronics, Allied Electronics, Scott's Odds and Ends [but Scott's minimum breaker rating is 10 amps] and other catalog sources.

This may be of some help. You can get parts from www.Mouser.com

http://www.jcstudiosinc.com/BlogShowThread?id=486&categoryId=

\

Dale H

Mouser has them, Radio Shack doesn't.

the part number is 625-1.5ke36ca.  

Still unsure if I need a fuse on both hot and common wires or only the hot wire?

I fuse the hot wire and also use a TVS between the hot and common wire. 

Just fuse the hot wire.

AC would it really make a difference? 

That would depend on how the commons are used.  If you have more than one power district, the correct method is to fuse all the hot leads.  Obviously, if you have a single power and common feed, either will do.

Since fusing the hot side is always correct, that's what I normally advise.

Does the TVS have a polarity, i.e. does it matter which side is connected to the A post?

Nope. no polarity, the TVS as specified by the number listed above is bi-directional, connect it either way.

Is there a way to periodically test the TVS to ensure that it is still functioning?  Could a multimeter be used?

There is no realistic test for a TVS outside of lab equipment.  For any test, it would have to be disconnected from the circuit.

I've tested them with a lamp and a high enough voltage to cause the breakdown.  The lamp is to limit the current through the TVS so you don't kill it in the testing process.  I use a variac to bring the voltage up to around 50 volts for the 36V ones I use, they actually make it a few volts higher and then the lamp starts coming on.  I use a pair of small 24 volt bulbs in series for the "load".

I normally just stick them in and forget them.  They're not like MOV devices that have a finite lifespan.