Don Phillipson wrote:
> My UPS, Belkin 375, was guaranteed for 3 years -- and just failed after 42
> months. The component obviously running too hot was not the battery
> (as expected) but the transformer. So I am undecided whether to
> replace the battery; I would not attempt to replace the transformer.
> 1. Is it normal for a (lead-acid) battery at the end of its life to cause
> UPS
> overheating and auto-off? (It is hard to imagine the transformer
> degrading or overheating by itself.)
> 2. Are there nowadays non-lead batteries (to replace a Ritar RT1240)
> that might work better?
>
That's possibly a Chinese battery.
http://www.ritarpower.com/About.aspx?id=11
Have you talked to Belkin yet ? What arrangements
will they make for transport ? Do you have to
ship it back for warranty service ? Or do they
offer authorized dealers near you ?
Transformers can get hot on their very own. I
have a transformer here (around 12V 4A), which
runs way too hot after sitting *idle* for an
hour plugged in. It's obvious some kind of
lamination failure has occurred, because it
didn't used to get hot like that. So the
transformer itself can fail, if eddy currents
flow through the laminations. Laminations are
coated, to stop that.
http://en.wikipedia.org/wiki/Transformer
"Later designs constructed the core by stacking
layers of thin steel laminations, a principle
that has remained in use. Each lamination is
insulated from its neighbors by a thin non-conducting
layer of insulation."
"The effect of laminations is to confine eddy
currents to highly elliptical paths that enclose
little flux, and so reduce their magnitude.
Thinner laminations reduce losses"
If the laminations short together, the loss
goes up, and the transformer gets hot. My
transformer still seems to product the
correct output (so it's not a shorted winding),
but at zero current flow, it still gets hot. And
that could be an eddy current problem (caused
by rusting). I can run the transformer for about
an hour, before I have to turn it off due to the
surface temperature reached.
I think I'd let Belkin sort this out.
Paul