What's inside an MRC Railpower Tech II 2500

[alhoop]

Well, inrush wasn't the issue here.  .........

Inrush is the issue when you asked about the rationale of using a slo-blo fuse.
If you will go back and read my post I said what peteski said in his post about using a slo-blo fuse and
inrush current being the rationale.

Your quote "Perhaps one of you gents will enlighten me. "
Read up on James Clerk Maxwell and his works which will lead you to Michael Faraday.
Just remember the power in the primary of a transformer is equal to the power in the secondary so
if you have 12 volts in the secondary pushing a short the current will be very high and thus
the current in the primary will be 1/10 of that or more than your 1 amp fuse.

Al

[mmagliaro]

I am not familiar with the details of transformer theory. There might be a current spike in the primary when the secondary gets shorted  (similar to inrush current).  But I don't know for sure.  Your power rating calculation is close. There is some power loss in the transformer, but that should not be double of the output rating.

Do you have a meter which could measure the short circuit AC current of the secondary?  I'm curious what the reading would be.

I'm afraid my investigative time with this pack is at an end.  It works reliably, the overload trips reliably, and all the functions work,
so I have boxed it up to return it to its owner.