36watts +72watts =108watts

I have a question along these lines, too. I have two transformers feeding my Legacy Powermaster. I believe this is fine, based on what I've read and also Mike's response, because:

1) The transformers are identical: Atlas/Williams 80w units.

2) Combined, they're under the 180w capacity of the Powermaster, so I assume they're also safely under the amperage and "OCP" of that unit as well. Everything runs nice and cool, though I admit I haven't induced any major shorts yet.

Am I missing anything? Thanks!

Alan P

Mike,

Like Bill, my electrical knowledge is weak.  I guess I'm not sure what you are gaining with your parallel transformer system (two PH135) when you fuse it to 7.5 amps.  I think an OCP of 7.5 amps would limit the power to the tracks to 135 watts.  Seems like one PH135 would meet your needs. 

There are several rules of thumb about parallel transformers.  One that immediately comes to mind is they should have identical specifications to properly share the load.

Truthfully, I think this is probably a bad idea, I'd just get a properly sized transformer.

I have to go along with 'gunrunnerjohn' on this one.

Just get a larger transformer from an online vendor or ebay if you trust ebay.

It's better to have too much power in a transformer then too little power.

Besides the smaller transformers can be used for lighting.

Lee Fritz

The LionChief wall packs are DC. The 72watt should work. Use the bend tab fix on the 5" & 10" track pieces of fastrack for good connection. Mike R has a video for it.

As has been said, these are DC output.  I suspect something of what was said above does apply, but I wish someone well versed in DC applications would answer this question.

I would not parallel transformers.  If their output voltages are not precisely equal, there will be current flow directly between them which could overheat portions of the secondary winding.  Phillyreading and Gunsmuggler John are absolutely correct.

AC or DC, the rules are pretty much the same, don't do it.

The simple answer is it's a bad idea.

It's not an impossible idea, but the hiccups and cautions (as cited above with great technical challenges) you need to deal with are not worth it.  Especially not just to get 108 watts.  

And it very well could damage/destroy one of the units in spectacular fashion (the "magic smoke" may be let out) in the process.  (If you don't know what I mean by magic smoke, that's an old electronics joke about letting out the magic smoke.  Item works before you let the magic smoke out by doing something like this, but then never works again once the smoke is let out.

This is one of those questions where if the person is asking, they are probably not technically prepared to deal with the ramifications of trying to successfully do it.

-Dave

THANKS TO ALL THAT REPLIED !

I will tell the customer the news !

Thanks all for the information !