PC power supplies

[Jimmy]

It is my understanding that PC powersupplies take 120 AC and run it through
a voltage doubler rectifying it and giving 300vdc. What I want to do is feed
300vdc into the powersupply via the line cord with no modification to the
power supply. As I dont have a schematic could someone please tell me if
this would work

 

[Spudley]

"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:iOFkb.33681$kZ5.12077@twister.southeast.rr.com...

It is my understanding that PC powersupplies take 120 AC and run it
through
a voltage doubler rectifying it and giving 300vdc. What I want to do
is feed
300vdc into the powersupply via the line cord with no modification
to the
power supply. As I dont have a schematic could someone please tell
me if
this would work

Where do you get your 300 Volt Direct Current (vdc) supply from?

That's Direct Current, not Alternating Current (AC)
It sure as hell doesn't come out from a wall outlet, as mains supplied
power is AC not DC.

If it is VDC then it could be applied straight across the large Filter
Capacitors. Making sure you have the correct polarity applied.
Positive rail to Positive and Negative supply rail applied to
Negative, else smoke and fire or bodily damage may result.

Sounds like a dangerous project to me.

 

[Rein Wiehler]

Jimmy wrote:

It is my understanding that PC powersupplies take 120 AC and run it
through a voltage doubler rectifying it and giving 300vdc. What I
want to do is feed 300vdc into the powersupply via the line cord with
no modification to the power supply. As I dont have a schematic could
someone please tell me if this would work

Warning!
what are you trying to dO? send smoke signals?
Who was telling you about 300vdc? to power up a PC?
A pc uses +5Vdc and +12VDc. so forget about your idea.

 

[Rein Wiehler]

Jimmy wrote:

It is my understanding that PC powersupplies take 120 AC and run it through
a voltage doubler rectifying it and giving 300vdc. What I want to do is feed
300vdc into the powersupply via the line cord with no modification to the
power supply. As I dont have a schematic could someone please tell me if
this would work

let everybody know when you are ready test so we know why the power
goes down again. Hopefully we can also see the smoke from your place.
rw

 

[Lenroc]

On Mon, 20 Oct 2003 00:15:10 +0000, Jimmy wrote:

It is my understanding that PC powersupplies take 120 AC and run it
through a voltage doubler rectifying it and giving 300vdc.

This is incorrect.

PC Power supplies take the power from the wall and turn it into DC, (up
to) 400 _Watts_ or so (depending on the power supply).

This is what my Power Supply provides on various leads:

+3.3V @ 28A
+5V @ 40A
+12V @ 18A
-12V @ 1A
-5V @ 1A
+5SB @ 3A (I admit I don't know what the SB means... I'm just reading
what's on the power supply...)

This is all maximum output.

--
Lenroc

 

[Wilson]

I agree with Spudley - its a dangerous thing to do. You are correct that
most offline switchers have this type of direct rectifier front end. While
this might work with a particular supply, you can't make assumptions about
it without detailed info on the supply you are using. Additionally, what
happens if the supply fails and someone replaces it with a different type or
model? There are no guarantees on internal polarity, or current ratings of
the various input devices.

You should look carefully at the DC ratings of the input line filter
components, (both coils and caps). I bet the "Y" capacitors on the input
lines are going to have a tough time with 300 VDC. They are probably
designed to have no DC bias. Capacitor heating is a concern because its
going to be higher for 300 VDC than for 120 VAC. Constant DC means constant
leakage, and this results in more internal heat. Add to that the effect of
higher voltage, and you could see capacitor failures or premature end of
life due to voltage stress.

Wilson

"Spudley" <antispam@bigpond.net.au> wrote in message
news:kHHkb.158061$bo1.97392@news-server.bigpond.net.au...

"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:iOFkb.33681$kZ5.12077@twister.southeast.rr.com...
It is my understanding that PC powersupplies take 120 AC and run it
through
a voltage doubler rectifying it and giving 300vdc. What I want to do
is feed
300vdc into the powersupply via the line cord with no modification
to the
power supply. As I dont have a schematic could someone please tell
me if
this would work

Where do you get your 300 Volt Direct Current (vdc) supply from?
That's Direct Current, not Alternating Current (AC)
It sure as hell doesn't come out from a wall outlet, as mains supplied
power is AC not DC.

If it is VDC then it could be applied straight across the large Filter
Capacitors. Making sure you have the correct polarity applied.
Positive rail to Positive and Negative supply rail applied to
Negative, else smoke and fire or bodily damage may result.

Sounds like a dangerous project to me.

 

[Jimmy]

What I have found so far is very incouraging. In the 120VAC mode the
rectifiers in the front end are working in a voltage doubler configuration
which would prohibit what I am trying to do. However in the 240 VAC mode
they work as a more conventional powersupply rectifying the 240 and allowing
it to come to the peak of the AC which is 300VDC. Still havent got this all
traced out yet, but think the rectifier configuration for 240VAC use is a
bridge. If so, the polarity of the input should not matter.

"Wilson" <sburke21702@yahoo.com> wrote in message
news:2c853eaeead91abb6fabf9137b6ab169@news.teranews.com...

I agree with Spudley - its a dangerous thing to do. You are correct that
most offline switchers have this type of direct rectifier front end. While
this might work with a particular supply, you can't make assumptions about
it without detailed info on the supply you are using. Additionally, what
happens if the supply fails and someone replaces it with a different type
or
model? There are no guarantees on internal polarity, or current ratings of
the various input devices.

You should look carefully at the DC ratings of the input line filter
components, (both coils and caps). I bet the "Y" capacitors on the input
lines are going to have a tough time with 300 VDC. They are probably
designed to have no DC bias. Capacitor heating is a concern because its
going to be higher for 300 VDC than for 120 VAC. Constant DC means
constant
leakage, and this results in more internal heat. Add to that the effect of
higher voltage, and you could see capacitor failures or premature end of
life due to voltage stress.

Wilson

"Spudley" <antispam@bigpond.net.au> wrote in message
news:kHHkb.158061$bo1.97392@news-server.bigpond.net.au...
"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:iOFkb.33681$kZ5.12077@twister.southeast.rr.com...
It is my understanding that PC powersupplies take 120 AC and run it
through
a voltage doubler rectifying it and giving 300vdc. What I want to do
is feed
300vdc into the powersupply via the line cord with no modification
to the
power supply. As I dont have a schematic could someone please tell
me if
this would work

Where do you get your 300 Volt Direct Current (vdc) supply from?
That's Direct Current, not Alternating Current (AC)
It sure as hell doesn't come out from a wall outlet, as mains supplied
power is AC not DC.

If it is VDC then it could be applied straight across the large Filter
Capacitors. Making sure you have the correct polarity applied.
Positive rail to Positive and Negative supply rail applied to
Negative, else smoke and fire or bodily damage may result.

Sounds like a dangerous project to me.

 

[Jimmy]

"Rein Wiehler" <rwiehler@netscape.net> wrote in message
news:Z1Ikb.96595$mf.33429@twister01.bloor.is.net.cable.rogers.com...

Jimmy wrote:

It is my understanding that PC powersupplies take 120 AC and run it
through a voltage doubler rectifying it and giving 300vdc. What I
want to do is feed 300vdc into the powersupply via the line cord with
no modification to the power supply. As I dont have a schematic could
someone please tell me if this would work

Warning!
what are you trying to dO? send smoke signals?
Who was telling you about 300vdc? to power up a PC?
A pc uses +5Vdc and +12VDc. so forget about your idea.

Thats funny mine says it will plug into 120 or 240 VAC. I never saw one that
plugged in 5 volts before. Must be getting close to sucess when people start
telling me it is impossible.

 

[Lenroc]

On Tue, 21 Oct 2003 20:00:20 +0000, Jimmy wrote:

A pc uses +5Vdc and +12VDc. so forget about your idea.

Thats funny mine says it will plug into 120 or 240 VAC. I never saw one that
plugged in 5 volts before. Must be getting close to sucess when people start
telling me it is impossible.

The Motherboard uses something like 12VDC, other components use 5VDC.

The Power Supply plugs into 120VAC or 240VAC.

--
Lenroc

 

[Jimmy]

Poked around inside the powersupply and found an eletrolytic cap with guess
what voltage on it, 300vdc. disconnected power supply from the line and
connected my 300vdc source across the cap. Works like a charm so far. All
normal outputs are present.Still need to find more about how the rectifiers
are configured before I am willing to run 300vdc in through the line Nay
sayers always bring me luck. Thanks lots guys.


"Jimmy" <Gfender@carolina.rr.com> wrote in message
newsfglb.39610$kZ5.6028@twister.southeast.rr.com...

"Rein Wiehler" <rwiehler@netscape.net> wrote in message
news:Z1Ikb.96595$mf.33429@twister01.bloor.is.net.cable.rogers.com...
Jimmy wrote:

It is my understanding that PC powersupplies take 120 AC and run it
through a voltage doubler rectifying it and giving 300vdc. What I
want to do is feed 300vdc into the powersupply via the line cord with
no modification to the power supply. As I dont have a schematic could
someone please tell me if this would work

Warning!
what are you trying to dO? send smoke signals?
Who was telling you about 300vdc? to power up a PC?
A pc uses +5Vdc and +12VDc. so forget about your idea.

Thats funny mine says it will plug into 120 or 240 VAC. I never saw one
that
plugged in 5 volts before. Must be getting close to sucess when people
start
telling me it is impossible.

 

[Spudley]

"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:QsYkb.35705$kZ5.33464@twister.southeast.rr.com...

What I have found so far is very incouraging. In the 120VAC mode the
rectifiers in the front end are working in a voltage doubler
configuration
which would prohibit what I am trying to do. However in the 240 VAC
mode
they work as a more conventional powersupply rectifying the 240 and
allowing
it to come to the peak of the AC which is 300VDC. Still havent got
this all
traced out yet, but think the rectifier configuration for 240VAC use
is a
bridge. If so, the polarity of the input should not matter.

It does not matter then, that's if you are applying your 300VDC prior
to the bridge rectifier "AC INPUTS" ~ ~ , as the bridge will provide
the correct polarity to the filter capacitors for you.

None the less, it is a rather dangerous exercise.

ps
I'm still curious as to where you obtain your 300VDC from, it must be
coming from another power supply, which seems kind of pointless to me,
if that is the case.

"Wilson" <sburke21702@yahoo.com> wrote in message
news:2c853eaeead91abb6fabf9137b6ab169@news.teranews.com...
I agree with Spudley - its a dangerous thing to do. You are
correct that
most offline switchers have this type of direct rectifier front
end. While
this might work with a particular supply, you can't make
assumptions about
it without detailed info on the supply you are using.
Additionally, what
happens if the supply fails and someone replaces it with a
different type
or
model? There are no guarantees on internal polarity, or current
ratings of
the various input devices.

You should look carefully at the DC ratings of the input line
filter
components, (both coils and caps). I bet the "Y" capacitors on the
input
lines are going to have a tough time with 300 VDC. They are
probably
designed to have no DC bias. Capacitor heating is a concern
because its
going to be higher for 300 VDC than for 120 VAC. Constant DC means
constant
leakage, and this results in more internal heat. Add to that the
effect of
higher voltage, and you could see capacitor failures or premature
end of
life due to voltage stress.

Wilson

"Spudley" <antispam@bigpond.net.au> wrote in message
news:kHHkb.158061$bo1.97392@news-server.bigpond.net.au...
"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:iOFkb.33681$kZ5.12077@twister.southeast.rr.com...
It is my understanding that PC powersupplies take 120 AC and
run it
through
a voltage doubler rectifying it and giving 300vdc. What I want
to do
is feed
300vdc into the powersupply via the line cord with no
modification
to the
power supply. As I dont have a schematic could someone please
tell
me if
this would work

Where do you get your 300 Volt Direct Current (vdc) supply from?
That's Direct Current, not Alternating Current (AC)
It sure as hell doesn't come out from a wall outlet, as mains
supplied
power is AC not DC.

If it is VDC then it could be applied straight across the large
Filter
Capacitors. Making sure you have the correct polarity applied.
Positive rail to Positive and Negative supply rail applied to
Negative, else smoke and fire or bodily damage may result.

Sounds like a dangerous project to me.

 

[Lenroc]

Spudley:

Please consider installing and using OE-QuoteFix
(http://flash.to/oe-quotefix).

If you will look over your last post, you will see that where you quoted
about 3 or 4 levels of quoted text, at the end of long lines, the number
of '>'s does not match the level of quoted text.

So, when you are quoting "Jimmy", anything written by him should have ">>
" in front of it, but in some places you end up with only "> ", making it
very hard to follow what you are saying.

Just installing OE-QuoteFix will fix this problem automatically, as well
as making news posts much easier to read for you.

This is not even mentioning the problem that you apparently quoted an
entire message, and put your new material in the middle, with nothing
added at either the top or the bottom. (In other words, you could stand to
learn how to snip too...)

In this case, I am quoting your entire message so you can see how it looks

Note: instead of installing OE-QuoteFix, you could instead just get a
better newsreader, but I'm not very likely to talk you into that

On Thu, 23 Oct 2003 15:31:23 +0000, Spudley wrote:

Subject: Re: PC power supplies
From: "Spudley" <antispam@bigpond.net.au
Newsgroups: alt.electronics
X-Newsreader: Microsoft Outlook Express 6.00.2800.1158
Date: Thu, 23 Oct 2003 15:31:23 GMT


"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:QsYkb.35705$kZ5.33464@twister.southeast.rr.com...
What I have found so far is very incouraging. In the 120VAC mode the
rectifiers in the front end are working in a voltage doubler
configuration
which would prohibit what I am trying to do. However in the 240 VAC
mode
they work as a more conventional powersupply rectifying the 240 and
allowing
it to come to the peak of the AC which is 300VDC. Still havent got
this all
traced out yet, but think the rectifier configuration for 240VAC use
is a
bridge. If so, the polarity of the input should not matter.


It does not matter then, that's if you are applying your 300VDC prior
to the bridge rectifier "AC INPUTS" ~ ~ , as the bridge will provide
the correct polarity to the filter capacitors for you.

None the less, it is a rather dangerous exercise.

ps
I'm still curious as to where you obtain your 300VDC from, it must be
coming from another power supply, which seems kind of pointless to me,
if that is the case.



"Wilson" <sburke21702@yahoo.com> wrote in message
news:2c853eaeead91abb6fabf9137b6ab169@news.teranews.com...
I agree with Spudley - its a dangerous thing to do. You are
correct that
most offline switchers have this type of direct rectifier front
end. While
this might work with a particular supply, you can't make
assumptions about
it without detailed info on the supply you are using.
Additionally, what
happens if the supply fails and someone replaces it with a
different type
or
model? There are no guarantees on internal polarity, or current
ratings of
the various input devices.

You should look carefully at the DC ratings of the input line
filter
components, (both coils and caps). I bet the "Y" capacitors on the
input
lines are going to have a tough time with 300 VDC. They are
probably
designed to have no DC bias. Capacitor heating is a concern
because its
going to be higher for 300 VDC than for 120 VAC. Constant DC means
constant
leakage, and this results in more internal heat. Add to that the
effect of
higher voltage, and you could see capacitor failures or premature
end of
life due to voltage stress.

Wilson

"Spudley" <antispam@bigpond.net.au> wrote in message
news:kHHkb.158061$bo1.97392@news-server.bigpond.net.au...
"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:iOFkb.33681$kZ5.12077@twister.southeast.rr.com...
It is my understanding that PC powersupplies take 120 AC and
run it
through
a voltage doubler rectifying it and giving 300vdc. What I want
to do
is feed
300vdc into the powersupply via the line cord with no
modification
to the
power supply. As I dont have a schematic could someone please
tell
me if
this would work

Where do you get your 300 Volt Direct Current (vdc) supply from?
That's Direct Current, not Alternating Current (AC)
It sure as hell doesn't come out from a wall outlet, as mains
supplied
power is AC not DC.

If it is VDC then it could be applied straight across the large
Filter
Capacitors. Making sure you have the correct polarity applied.
Positive rail to Positive and Negative supply rail applied to
Negative, else smoke and fire or bodily damage may result.

Sounds like a dangerous project to me.

 

[Spudley]

I have just installed OE-QuoteFix, here's hoping that it fixes the
problems you are referring to.

Thanks Lenroc for the pointers.


Lenroc wrote:

Spudley:

Please consider installing and using OE-QuoteFix
(http://flash.to/oe-quotefix).

If you will look over your last post, you will see that where you
quoted about 3 or 4 levels of quoted text, at the end of long lines,
the number
of '>'s does not match the level of quoted text.

So, when you are quoting "Jimmy", anything written by him should
have
">> " in front of it, but in some places you end up with only "> ",
making it very hard to follow what you are saying.

Just installing OE-QuoteFix will fix this problem automatically, as
well
as making news posts much easier to read for you.

This is not even mentioning the problem that you apparently quoted
an
entire message, and put your new material in the middle, with
nothing
added at either the top or the bottom. (In other words, you could
stand to learn how to snip too...)

In this case, I am quoting your entire message so you can see how it
looks

Note: instead of installing OE-QuoteFix, you could instead just get
a
better newsreader, but I'm not very likely to talk you into that

On Thu, 23 Oct 2003 15:31:23 +0000, Spudley wrote:

Subject: Re: PC power supplies
From: "Spudley" <antispam@bigpond.net.au
Newsgroups: alt.electronics
X-Newsreader: Microsoft Outlook Express 6.00.2800.1158
Date: Thu, 23 Oct 2003 15:31:23 GMT


"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:QsYkb.35705$kZ5.33464@twister.southeast.rr.com...
What I have found so far is very incouraging. In the 120VAC mode
the
rectifiers in the front end are working in a voltage doubler
configuration which would prohibit what I am trying to do. However
in the 240 VAC
mode
they work as a more conventional powersupply rectifying the 240
and
allowing it to come to the peak of the AC which is 300VDC. Still
havent got
this all
traced out yet, but think the rectifier configuration for 240VAC
use
is a
bridge. If so, the polarity of the input should not matter.

I am including the whole of the message in an effort to see how
effective OE-QuoteFix
really is.

It does not matter then, that's if you are applying your 300VDC
prior
to the bridge rectifier "AC INPUTS" ~ ~ , as the bridge will
provide
the correct polarity to the filter capacitors for you.

None the less, it is a rather dangerous exercise.

ps
I'm still curious as to where you obtain your 300VDC from, it must
be
coming from another power supply, which seems kind of pointless to
me, if that is the case.



"Wilson" <sburke21702@yahoo.com> wrote in message
news:2c853eaeead91abb6fabf9137b6ab169@news.teranews.com...
I agree with Spudley - its a dangerous thing to do. You are
correct that
most offline switchers have this type of direct rectifier front
end. While
this might work with a particular supply, you can't make
assumptions about
it without detailed info on the supply you are using.
Additionally, what
happens if the supply fails and someone replaces it with a
different type or model? There are no guarantees on internal
polarity, or current
ratings of
the various input devices.

You should look carefully at the DC ratings of the input line
filter
components, (both coils and caps). I bet the "Y" capacitors on
the
input lines are going to have a tough time with 300 VDC. They are
probably
designed to have no DC bias. Capacitor heating is a concern
because its
going to be higher for 300 VDC than for 120 VAC. Constant DC
means
constant leakage, and this results in more internal heat. Add to
that the
effect of
higher voltage, and you could see capacitor failures or premature
end of
life due to voltage stress.

Wilson

"Spudley" <antispam@bigpond.net.au> wrote in message
news:kHHkb.158061$bo1.97392@news-server.bigpond.net.au...
"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:iOFkb.33681$kZ5.12077@twister.southeast.rr.com...
It is my understanding that PC powersupplies take 120 AC and
run
it through a voltage doubler rectifying it and giving 300vdc.
What I want to do is feed 300vdc into the powersupply via the
line cord with no modification to the power supply. As I dont
have a schematic could someone please tell me if this would
work

Where do you get your 300 Volt Direct Current (vdc) supply from?
That's Direct Current, not Alternating Current (AC)
It sure as hell doesn't come out from a wall outlet, as mains
supplied power is AC not DC.

If it is VDC then it could be applied straight across the large
Filter Capacitors. Making sure you have the correct polarity
applied. Positive rail to Positive and Negative supply rail
applied to Negative, else smoke and fire or bodily damage may
result.

Sounds like a dangerous project to me.

 

[Jimmy]

"Spudley" <antispam@bigpond.net.au> wrote in message
news:fvSlb.162743$bo1.101191@news-server.bigpond.net.au...

"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:QsYkb.35705$kZ5.33464@twister.southeast.rr.com...
What I have found so far is very incouraging. In the 120VAC mode the
rectifiers in the front end are working in a voltage doubler
configuration
which would prohibit what I am trying to do. However in the 240 VAC
mode
they work as a more conventional powersupply rectifying the 240 and
allowing
it to come to the peak of the AC which is 300VDC. Still havent got
this all
traced out yet, but think the rectifier configuration for 240VAC use
is a
bridge. If so, the polarity of the input should not matter.


It does not matter then, that's if you are applying your 300VDC prior
to the bridge rectifier "AC INPUTS" ~ ~ , as the bridge will provide
the correct polarity to the filter capacitors for you.

None the less, it is a rather dangerous exercise.

ps
I'm still curious as to where you obtain your 300VDC from, it must be
coming from another power supply, which seems kind of pointless to me,
if that is the case.
**************

300 vdc powers supply works off of 24 vdc input. Origonaly unit was designed
to feed up to 4 DC to DC converters that gave +- 5 and +-15vdc output. I am
going to use it in my diesel school bus turned RV to power a PC which will
be the heart of a navigation/ entertainment center.

"Wilson" <sburke21702@yahoo.com> wrote in message
news:2c853eaeead91abb6fabf9137b6ab169@news.teranews.com...
I agree with Spudley - its a dangerous thing to do. You are
correct that
most offline switchers have this type of direct rectifier front
end. While
this might work with a particular supply, you can't make
assumptions about
it without detailed info on the supply you are using.
Additionally, what
happens if the supply fails and someone replaces it with a
different type
or
model? There are no guarantees on internal polarity, or current
ratings of
the various input devices.

You should look carefully at the DC ratings of the input line
filter
components, (both coils and caps). I bet the "Y" capacitors on the
input
lines are going to have a tough time with 300 VDC. They are
probably
designed to have no DC bias. Capacitor heating is a concern
because its
going to be higher for 300 VDC than for 120 VAC. Constant DC means
constant
leakage, and this results in more internal heat. Add to that the
effect of
higher voltage, and you could see capacitor failures or premature
end of
life due to voltage stress.

Wilson

"Spudley" <antispam@bigpond.net.au> wrote in message
news:kHHkb.158061$bo1.97392@news-server.bigpond.net.au...
"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:iOFkb.33681$kZ5.12077@twister.southeast.rr.com...
It is my understanding that PC powersupplies take 120 AC and
run it
through
a voltage doubler rectifying it and giving 300vdc. What I want
to do
is feed
300vdc into the powersupply via the line cord with no
modification
to the
power supply. As I dont have a schematic could someone please
tell
me if
this would work

Where do you get your 300 Volt Direct Current (vdc) supply from?
That's Direct Current, not Alternating Current (AC)
It sure as hell doesn't come out from a wall outlet, as mains
supplied
power is AC not DC.

If it is VDC then it could be applied straight across the large
Filter
Capacitors. Making sure you have the correct polarity applied.
Positive rail to Positive and Negative supply rail applied to
Negative, else smoke and fire or bodily damage may result.

Sounds like a dangerous project to me.

 

[Spudley]

<snip>

ps
I'm still curious as to where you obtain your 300VDC from, it must
be
coming from another power supply, which seems kind of pointless to
me, if that is the case.
**************
300 vdc powers supply works off of 24 vdc input. Origonaly unit was
designed to feed up to 4 DC to DC converters that gave +- 5 and
+-15vdc output. I am going to use it in my diesel school bus turned
RV to power a PC which will be the heart of a navigation/
entertainment center.

Sounds like a worth while exercise then.
Good luck and I hope you don't damage something doing it, especially
yourself.



<snip>