Why don't they put circuit breakers in PS'?

  • Thread starter Thread starter Ron
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R

Ron

Just a thought. Instead of fuses why don't they put breakers in power
supplies? It'd sure as hell save you a lot of hassle buying a new one.
 
Ron said:
Just a thought. Instead of fuses why don't they put breakers in power
supplies? It'd sure as hell save you a lot of hassle buying a new one.
Click to expand...

Becuase there should be no problem or event in a system that should blow a
breaker.
It's the way they are certifed by codes and it's probably best for all
concerned, otherwise so idiot could continually reset it and evenentually a
fire coud start anyway.
 
Just a thought.
Click to expand...

Dangerous business those. If you start getting
brown smelly stuff dripping from your ears, you'll
know that you've overdone that thinking stuff.

Unfortunately for you, by then the damage is terminal.
Instead of fuses why don't they put breakers in power supplies?
Click to expand...

There is an electronic breaker that shuts down the
power supply when the output current is too high or
the output voltage gets outside the legal range, and
that acts much faster than any breaker can act.
It'd sure as hell save you a lot of hassle buying a new one.
Click to expand...

The fuse normally only blows when something has failed,
usually the rectification of the mains, usually a diode etc.
So it aint just a matter of resetting a breaker. The fuse
is basically there to prevent a fire after a failure.
 
Just a thought. Instead of fuses why don't they put breakers in power
supplies? It'd sure as hell save you a lot of hassle buying a new one.
Click to expand...

Cost and benefit. SInce 99.9 % of the PSUs go into boxes with known
and very predictable power requirements they are are simply preventing
fire if someone should drop a screw while working on a live system,
which should never happen, and rareley does. If you are poping fuses
you're doing something wrong.
 
Previously Ron said:
Just a thought. Instead of fuses why don't they put breakers in power
supplies? It'd sure as hell save you a lot of hassle buying a new one.
Click to expand...

These fuses are not there to procect the PSU. They are there
to prevent fire. If they melt, something very bad has already
happened. PSU protection is in the PSU circuit (or none if
it is a cheap one). My PSU here, e.g., has short-circuit, over-
voltage and overload protection. It also has a fuse. If that
ever blows, I fully expect my PSU to be dead, since some of the
protection circuitry has to have malfunctioned.

Other aspect is that in order to protect semiconductorf from
damage with fises, they have to be ultra-fast, miliseconds
may already be too slow. There are some fuses designed for such
fast times, but they are very expensive. Circuit breakers are
at least an order of magnitude slower.

Arno
 
These fuses are not there to procect the PSU. They are there
to prevent fire. If they melt, something very bad has already
happened. PSU protection is in the PSU circuit (or none if
it is a cheap one). My PSU here, e.g., has short-circuit, over-
voltage and overload protection. It also has a fuse. If that
ever blows, I fully expect my PSU to be dead, since some of the
protection circuitry has to have malfunctioned.

Other aspect is that in order to protect semiconductorf from
damage with fises, they have to be ultra-fast, miliseconds
may already be too slow. There are some fuses designed for such
fast times, but they are very expensive. Circuit breakers are
at least an order of magnitude slower.
Click to expand...

Circuit breakers for the kind of amperage a PSU provides
are not cheap, or small.
 
ATX is required to have electronic short circuit protection. The fuse is just
fire protection.
 
Circuit breakers for the kind of amperage
a PSU provides are not cheap, or small.
Click to expand...

A breaker where the mains fuse is doesnt have that problem tho.

The real reason they arent uses is because that fuse
normally only blows when the PSU has died and since
it needs to be opened to fix what has died if that is done,
its easy enough to change the fuse at the same time.
 
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