28 Apr
2000
28 Apr
'00
7:38 a.m.
ard
I've shorted these units accidentally (typically
the multiple output
connectors manage to touch each other) and had them get _very_ hot
without burning out the transformer. Hot enough to melt the plastic
sleeving on the electrolytics, etc. And hot enough that I couldn't hold
the case. In no case did the primary winding open, and there was no fuse
or thermal fuse anywhere in the circuit.
Hi Tony
They probably cheated on the wire. The insulation
on the primary wire is suppose to melt, shorting turns.
This is suppose to cause the incoming fine wire, that
leads from the lugs to the primary, to burn open.
This is what they are tested to do but like anything,
some purchasing agent may have seen that wire x was
cheaper at company xx and made the change without
realizing the reasons for using a particular wire.
These are the kinds of problems that the ISO stuff
was suppose to stop but it seems it is only good
for lawers that back track booboos. Since UL can't
look at every unit shipped, the entire thing is
subject to human error.
Dwight