24-30v dc power supply schematic

[chas]

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
.. . . in advance to one and all. . .thanks. .. chas.

 

[John Fields]

On Sun, 28 Oct 2012 23:44:16 -0600, "chas" <footboarder@bresnan.net>
wrote:

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.

---
View using a fixed-pitch font:


+-[BFD>]----------+-->OUT+
MAINS>-----+ +-+ |
BFT | | +-[<BFD]-+--------|-->OUT-
\ P||S | |
R||E +-[BFC+]-+
I||C | |
| | +-[<BFD]-+ |
MAINS>-----+ +-+ |
+-[BFD>]----------+

BFT:
http://www.signaltransformer.com/sites/all/pdf/Rectifiers.pdf

BFC:
http://www.cde.com/catalogs/CGS.pdf

BFD:
http://www.vishay.com/docs/88612/gbpc12.pdf


--
JF

 

[Rick]

"John Fields" <jfields@austininstruments.com> wrote in message
news:2ads88lji0meb9nqrpucig9bh7kbhvpkrb@4ax.com...

On Sun, 28 Oct 2012 23:44:16 -0600, "chas" <footboarder@bresnan.net
wrote:

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.


---
View using a fixed-pitch font:


+-[BFD>]----------+-->OUT+
MAINS>-----+ +-+ |
BFT | | +-[<BFD]-+--------|-->OUT-
\ P||S | |
R||E +-[BFC+]-+
I||C | |
| | +-[<BFD]-+ |
MAINS>-----+ +-+ |
+-[BFD>]----------+

BFT:
http://www.signaltransformer.com/sites/all/pdf/Rectifiers.pdf

BFC:
http://www.cde.com/catalogs/CGS.pdf

BFD:
http://www.vishay.com/docs/88612/gbpc12.pdf


--
JF

For high current designs a full wave using a center tap transformer is more
efficient, it makes better use of the iron in the transformer and you only
have one diode drop.

http://www.hammondmfg.com/pdf/5c007.pdf

 

[Jamie]

chas wrote:

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.

Let me get this correct here, you'd be happy with a 24V AC or
20v DC supply?


Jamie

 

[chas]

120 v AC imput and either 24 or 30 v DC output. Need higher output amps for
the furnace.
******************************************
"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:sGujs.4256$iq6.3428@newsfe21.iad...

chas wrote:
I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.



Let me get this correct here, you'd be happy with a 24V AC or
20v DC supply?


Jamie

 

[chas]

I'm at a loss on how to view this.
************************************
"John Fields" <jfields@austininstruments.com> wrote in message
news:2ads88lji0meb9nqrpucig9bh7kbhvpkrb@4ax.com...

On Sun, 28 Oct 2012 23:44:16 -0600, "chas" <footboarder@bresnan.net
wrote:

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.


---
View using a fixed-pitch font:


+-[BFD>]----------+-->OUT+
MAINS>-----+ +-+ |
BFT | | +-[<BFD]-+--------|-->OUT-
\ P||S | |
R||E +-[BFC+]-+
I||C | |
| | +-[<BFD]-+ |
MAINS>-----+ +-+ |
+-[BFD>]----------+

BFT:
http://www.signaltransformer.com/sites/all/pdf/Rectifiers.pdf

BFC:
http://www.cde.com/catalogs/CGS.pdf

BFD:
http://www.vishay.com/docs/88612/gbpc12.pdf


--
JF

 

[John Fields]

On Mon, 29 Oct 2012 09:52:53 -0600, "chas" <footboarder@bresnan.net>
wrote:

I'm at a loss on how to view this.
************************************

---
Please bottom-post.

Fixed-pitch fonts are ones that have equal spacing between characters,
like Courier.

Variable-pitch fonts are ones that don't have equal spacing between
characters, like Times Roman.

If you view ASCII art with a variable-pitch font, the result will
generally be an unintelligible mess.

Also, it's a good idea to start each line of an ASCIImatic with a
character other than a space in order to keep some newsreaders from
deleting a space if the first character in the line is a space.

I forgot to and my drawing got messed up; here's how it's supposed to
look:

.. +-[BFD>]----------+-->OUT+
..MAINS>-----+ +-+ |
.. BFT | | +-[<BFD]-+--------|-->OUT-
.. \ P||S | |
.. R||E +-[BFC+]-+
.. I||C | |
.. | | +-[<BFD]-+ |
..MAINS>-----+ +-+ |
.. +-[BFD>]----------+


--
JF

 

[John Fields]

On Mon, 29 Oct 2012 06:02:18 -0500, "Rick" <rike22@bellsouth.net>
wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:2ads88lji0meb9nqrpucig9bh7kbhvpkrb@4ax.com...
On Sun, 28 Oct 2012 23:44:16 -0600, "chas" <footboarder@bresnan.net
wrote:

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.


---
View using a fixed-pitch font:


+-[BFD>]----------+-->OUT+
MAINS>-----+ +-+ |
BFT | | +-[<BFD]-+--------|-->OUT-
\ P||S | |
R||E +-[BFC+]-+
I||C | |
| | +-[<BFD]-+ |
MAINS>-----+ +-+ |
+-[BFD>]----------+

BFT:
http://www.signaltransformer.com/sites/all/pdf/Rectifiers.pdf

BFC:
http://www.cde.com/catalogs/CGS.pdf

BFD:
http://www.vishay.com/docs/88612/gbpc12.pdf


--
JF

For high current designs a full wave using a center tap transformer is more
efficient, it makes better use of the iron in the transformer and you only
have one diode drop.

---
I disagree.

With a bridge you're using all of the secondary all of the time, while
with FWCT you're using half of the secondary half of the time and the
other half of the secondary the other half of the time.

Also, FWCT takes twice the number of turns on the secondary and the
rectifiers have to stand off twice the reverse voltage.

--
JF

 

[Cydrome Leader]

chas <footboarder@bresnan.net> wrote:

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.

you're going to make an induction furnace, but need help with the brute
force power supply?

a plain bridge rectifier and some giant caps is probably fine for what you
need. something around 20VAC from the transformer will be about right.

 

[P E Schoen]

"chas" wrote in message news:TIojs.28$Ns4.1@newsfe09.iad...

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.

Since you only need about 300 watts you might be able to use the 12 VDC from
a couple of old computer power supplies, in series. A 400W supply usually
has 12V at 15 amps or more. You may even be able to hack it to get what you
need with one unit, and if you can use the frequency of the supply for the
induction furnace, you may be able to tap off before the output rectifier
and use it directly on your induction coil.
http://www.mpja.com/Dual-250Watt-Reundant-Computer-Power-Supply/productinfo/17094+PS/
(12V 14A, $10)
http://www.mpja.com/650Watt-ATX-Echo-Star-Computer-Power-Supply/productinfo/17980+PS/
(12V 22A, $16)

You can also get single output switching power supplies for 15 amps or more:
http://www.mpja.com/12V-17A-Phihong-Power-Supply/productinfo/18091+PS/ ($15)

Paul

 

[Jamie]

P E Schoen wrote:

"chas" wrote in message news:TIojs.28$Ns4.1@newsfe09.iad...

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.


Since you only need about 300 watts you might be able to use the 12 VDC
from a couple of old computer power supplies, in series. A 400W supply
usually has 12V at 15 amps or more. You may even be able to hack it to
get what you need with one unit, and if you can use the frequency of the
supply for the induction furnace, you may be able to tap off before the
output rectifier and use it directly on your induction coil.
http://www.mpja.com/Dual-250Watt-Reundant-Computer-Power-Supply/productinfo/17094+PS/
(12V 14A, $10)
http://www.mpja.com/650Watt-ATX-Echo-Star-Computer-Power-Supply/productinfo/17980+PS/
(12V 22A, $16)

You can also get single output switching power supplies for 15 amps or
more:
http://www.mpja.com/12V-17A-Phihong-Power-Supply/productinfo/18091+PS/
($15)

Paul


actually, I was thinking he could gets his hands on a 24 volt charger

from an auto parts store.

I have a large garage charger I gutted out and made a heavy duty 13.8
volt supply to test run 12 volt auto equipment.. I got large caps in
there filling the hole and a soft start. N channel power mosfets sinking
the (-) side output through an inductor to switch mode regulate it.

Works a treat, the caps are in 2 stages, one set before the switch and
another set after.

I figure even if it fets shorted, the full output isn't that much
higher, some equipment should handle it.

Jamie

 

[Michael A. Terrell]

P E Schoen wrote:

"chas" wrote in message news:TIojs.28$Ns4.1@newsfe09.iad...

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.

Since you only need about 300 watts you might be able to use the 12 VDC from
a couple of old computer power supplies, in series. A 400W supply usually
has 12V at 15 amps or more. You may even be able to hack it to get what you
need with one unit, and if you can use the frequency of the supply for the
induction furnace, you may be able to tap off before the output rectifier
and use it directly on your induction coil.
http://www.mpja.com/Dual-250Watt-Reundant-Computer-Power-Supply/productinfo/17094+PS/
(12V 14A, $10)
http://www.mpja.com/650Watt-ATX-Echo-Star-Computer-Power-Supply/productinfo/17980+PS/
(12V 22A, $16)

Bad idea. The negative is tied to the case, and the power line
neutral.

You can also get single output switching power supplies for 15 amps or more:
http://www.mpja.com/12V-17A-Phihong-Power-Supply/productinfo/18091+PS/ ($15)

 

[Les Cargill]

John Fields wrote:

On Mon, 29 Oct 2012 06:02:18 -0500, "Rick" <rike22@bellsouth.net
wrote:


"John Fields" <jfields@austininstruments.com> wrote in message
news:2ads88lji0meb9nqrpucig9bh7kbhvpkrb@4ax.com...
On Sun, 28 Oct 2012 23:44:16 -0600, "chas" <footboarder@bresnan.net
wrote:

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.


---
View using a fixed-pitch font:


+-[BFD>]----------+-->OUT+
MAINS>-----+ +-+ |
BFT | | +-[<BFD]-+--------|-->OUT-
\ P||S | |
R||E +-[BFC+]-+
I||C | |
| | +-[<BFD]-+ |
MAINS>-----+ +-+ |
+-[BFD>]----------+

BFT:
http://www.signaltransformer.com/sites/all/pdf/Rectifiers.pdf

BFC:
http://www.cde.com/catalogs/CGS.pdf

BFD:
http://www.vishay.com/docs/88612/gbpc12.pdf


--
JF

For high current designs a full wave using a center tap transformer is more
efficient, it makes better use of the iron in the transformer and you only
have one diode drop.

---
I disagree.

With a bridge you're using all of the secondary all of the time, while
with FWCT you're using half of the secondary half of the time and the
other half of the secondary the other half of the time.

Also, FWCT takes twice the number of turns on the secondary and the
rectifiers have to stand off twice the reverse voltage.

That's what I'd always heard. You need center tap only if you
need output balanced about zero. It's also easier to filter the
output from the bridge with a solid ground reference.

--
Les Cargill

 

[Jasen Betts]

On 2012-10-29, P E Schoen <paul@peschoen.com> wrote:

"chas" wrote in message news:TIojs.28$Ns4.1@newsfe09.iad...

I need a schematic for a non regulated 24 or 20v dc power supply.
I will be running high amps (15?) for a homebuilt induction furnace.
. . . in advance to one and all. . .thanks. .. chas.

Since you only need about 300 watts you might be able to use the 12 VDC from
a couple of old computer power supplies, in series.

that only wrks if you plug one of them into an isolating transformer.

--
⚂⚃ 100% natural

 

[whit3rd]

On Sunday, October 28, 2012 10:44:19 PM UTC-7, chas wrote:

I need a schematic for a non regulated 24 or 20v dc power supply.

I will be running high amps (15?) for a homebuilt induction furnace.

An easy option is two car batteries in series, with a couple of
chargers attached. If the induction furnace only operates for a
few minutes at a time, you can switch the batteries from series to
parallel and charge 'em offline.

Anything DC has to be filtered, if not regulated, and 15A of ripple
current is going to require some thought. Car batteries might
be overkill, but as long as the problem gets dead...

If you decide to get a regulated supply, there's surplus options. Consider:

<http://www.mpja.com/24V-125A-Hengfu-Power-Supply/productinfo/16489+PS/>

 

[Phil Allison]

"Rick"

For high current designs a full wave using a center tap transformer is
more efficient, it makes better use of the iron in the transformer ...

** That is 100% WRONG !!!!!!

http://www.hammondmfg.com/pdf/5c007.pdf

** The link is full of damn silly errors, shame on Hammond.

A full wave bridge plus filter cap is the most efficient by far.

And to a close approximation, peak DC and average DC are the SAME !!



.... Phil

 

[P E Schoen]

"Michael A. Terrell" wrote in message
news:dZSdnQIIeqKvehPNnZ2dnUVZ_g-dnZ2d@earthlink.com...

P E Schoen wrote:

Since you only need about 300 watts you might be able to use the
12 VDC from a couple of old computer power supplies, in series.

Bad idea. The negative is tied to the case, and the power line neutral.

The negative MAY be connected to the case, but certainly not to the power
line neutral. So you may be able to remove the case ground connection, or
just float the second supply case 12VDC above the other. Here is a schematic
of a 300W ATX supply showing the separate grounds:
http://www.smpspowersupply.com/ATX_power_supply_schematic.pdf

Paul

 

[P E Schoen]

"P E Schoen" wrote in message news:k6qav6$m2g$1@dont-email.me...

The negative MAY be connected to the case, but certainly not to the power
line neutral. So you may be able to remove the case ground connection, or
just float the second supply case 12VDC above the other. Here is a
schematic of a 300W ATX supply showing the separate grounds:
http://www.smpspowersupply.com/ATX_power_supply_schematic.pdf

Here is an article about using two server PSUs for 24 VDC:
https://sites.google.com/site/tjinguytech/my-projects/diy-24v-47a

And here is a good article about using components from a PSU to build your
own, with high efficiency synchronous rectifiers:
http://www.qrp4u.de/docs/en/smps_new/index.htm

Paul

 

[Michael A. Terrell]

P E Schoen wrote:

"P E Schoen" wrote in message news:k6qav6$m2g$1@dont-email.me...

The negative MAY be connected to the case, but certainly not to the power
line neutral. So you may be able to remove the case ground connection, or
just float the second supply case 12VDC above the other. Here is a
schematic of a 300W ATX supply showing the separate grounds:
http://www.smpspowersupply.com/ATX_power_supply_schematic.pdf

Every PC power supply I have, has the negative connected to the
ground pin.

Here is an article about using two server PSUs for 24 VDC:
https://sites.google.com/site/tjinguytech/my-projects/diy-24v-47a

And here is a good article about using components from a PSU to build your
own, with high efficiency synchronous rectifiers:
http://www.qrp4u.de/docs/en/smps_new/index.htm

What about the leakage current from the PFC, and EMI caused by an
ungrounded supply? You can do lots of things that aren't good ideas.

 

[Cydrome Leader]

Phil Allison <phil_a@tpg.com.au> wrote:

"Rick"


For high current designs a full wave using a center tap transformer is
more efficient, it makes better use of the iron in the transformer ...

** That is 100% WRONG !!!!!!


http://www.hammondmfg.com/pdf/5c007.pdf


** The link is full of damn silly errors, shame on Hammond.

A full wave bridge plus filter cap is the most efficient by far.

that depends on the voltage you want from the power supply. If you want a
low voltage high current supply, a bridge rectifier can be a poor choice.

And to a close approximation, peak DC and average DC are the SAME !!

that's if there's no ripple. They never defined it, so yeah you could
question the pdf.