Overvoltage protection for Seasonic S12 600 watt power supply ?

[Skybuck]

Hello,

A power company in the Netherlands caused a voltage "punch" of 300
volts in some cities.
(Damaging many computers, magnetrons, tv's, etc )

The normal voltage level is 220 volts.

Is the Seasonic S12 600 watt power supply able to survive 300 volts ?

The product's manual, advertisement and the website mention
"overvoltage protection".

What is overvoltage ? I assume it means higher voltage than normal ?

What is overvoltage protection ?

What does it protect ?

(Does it protect the power supply itself ? Does it protect the rest of
the computer components ?)

Can you explain a little bit how overvoltage protection works ?

Does it protect against any voltage ?

Or does it only protect up to a certain voltage ?

I also contacted Seasonic support.

Bye,
Skybuck.

 

[Homer J Simpson]

A power company in the Netherlands caused a voltage "punch" of 300
volts in some cities.

A local power company dropped an 11 kV line onto the local 110 volt line.
Bad, bad, bad, bad, bad, bad!

 

[[email protected]]

Regarding over voltage.

Mostly the words "over voltage protection" do actually mean "transient
protection". This means a short duration high volttage pulse (in the
kV range during microsec.) can be absorbed by the power supply without
damage. Also lower voltage peaks with somewhat longer duration (ms) can
be absorbed by the transient protection.

Many times Varistors (VDR) are used at the Mains input in combination
with filters. Varistors can handle large currents for a short time but
will run hot or even may rupture in case of moderate overload for
prolonged time (due to over dissipation).

According to the media (I live in the Netherlands), the over voltage
took about 20 minutes and was 300 V. We may assume that 300Vrms is
mend. This voltage is not that high that a primary fuse will blow
immediately, so this is a main reason for lots of damage (and damage
that still has to occur because of stressed components).

Regarding your power supply, I checked the "data sheet" but the data
sheet doesn't give much information. Whether this supply can handle
this overload depends on many things.

I believe the best thing you can do is try to find out what happened
exactly (overload voltage and duration) and contact the manufacturer.
It is possible that the power supply did survive the overload, but will
fail within months.

Regarding protection.
Electronic equipment has to have some form of transient over voltage
protection to fulfill basic requirements (CE for European Union). It is
free to the manufacturer to do actual testing. Often products can be
found that has no protection (or the components are not on the PCB
while the footprints are).

There are few requirements for prolonged mains over voltage. Most
equipment is designed to handle mains voltage + 10%. When higher mains
voltage is applied (as recently in the Netherlands), the only
requirement is that no dangerous situation occurs (like fire, electric
shock, etc). This means equipment may fail.

Power supplies may have protection for the low voltage outputs (in case
of the power supply fails). The last resort protection is mostly a
so-called "crowbar". This circuit is connected in parallel to the
output to be protected. It generated a short circuit when the output
voltage (for example 5V) exceeds a certain threshold. The short circuit
(mostly done by a "thyristor") does blow a fuse or other device
preventing further damage to the low voltage circuitry (like the
motherboard).

I hope this will help you a bit.

Best regards,

Wim

 

[w_tom]

Overvoltage protection means the 3.3, 5, and 12 volt outputs will not
get too high as to damage computer components. This concept has been
industry standard for generations. A power supply - even when it fails
- must never damage any computer parts.

Overvoltage protection is not transient protection from AC mains. It
is clearly defined even in Intel power supply requirements - with
numbers:

Table 11: Overvoltage Protection
Output
+12 VDC Max is 15.6 volts
+5 VDC Nominal is 6.3 volts
+3.3 VDC Nominal is 4.2 volts

Meanwhile other industry standard specs demand that an appliance even
withstand 600 volts without damage. Computer power supplies are
supposed to be more robust. They should even withstand thousands of
volts without damage - again as even defined in specifications with
another important parameter - time.

Overvoltage protection is a circuit that detects that overvoltage and
then lock out the supply. This protection feature requires power be
completely removed to be reset.

Notice another feature also required by same specs in all supplies.
Short all power supply output wires together and no power supply damage
can occur. Of course many computer 'experts' don't have basic
electrical knowledge. They buy power supplies on price. Therefore
some power supplies can be damaged by that short circuit AND are also
missing overvoltage protection.

Overvoltage protection is a defacto standard concept known by anyone
with technical power supply experience. A term so well understood that
overvoltage protection need not be defined.

 

[[email protected]]

Hello,

A power company in the Netherlands caused a voltage "punch" of 300
volts in some cities.
(Damaging many computers, magnetrons, tv's, etc )

The normal voltage level is 220 volts.

Is the Seasonic S12 600 watt power supply able to survive 300 volts ?

The product's manual, advertisement and the website mention
"overvoltage protection".

What is overvoltage ? I assume it means higher voltage than normal ?

What is overvoltage protection ?

What does it protect ?

(Does it protect the power supply itself ? Does it protect the rest of
the computer components ?)

Can you explain a little bit how overvoltage protection works ?

Does it protect against any voltage ?

Or does it only protect up to a certain voltage ?

I also contacted Seasonic support.

Bye,
Skybuck.

I use the same brand supply. I have a gut feeling it will be OK. This
is a SMPS that works from 100 up to 240, so it is engineered for a very
wide voltage range. While 25% overage is pretty bad, there could be
significant guard-banding in this design as it is not a cheap power
supply.

I never did an off-line switcher design, but that is what you would
want to research.