40-0-40 @8A+8A transformer to 40vdc @ 16A - Possible?

R

RayGilbert

Guest
Hi,
Is there a proven method to rectify a 40-0-40 hardwired centre tapped
transformer using both of the windings for fairly high current
application.
I would prefer a method with little or no smoke and absolutely no loud
bangs :)
TIA
Raymond Gilbert
 
"RayGilbert" <raygilbert@lineone.net> wrote in message
news:5708f106.0312191702.43bd68a9@posting.google.com...
Hi,
Is there a proven method to rectify a 40-0-40 hardwired centre tapped
transformer using both of the windings for fairly high current
application.
I would prefer a method with little or no smoke and absolutely no loud
bangs :)
TIA
Raymond Gilbert
Click to expand...
You will have to find a way to seperate the two windings, ie the centre tap.
If the outcoming center tap is just one cable (Not two wires twisted etc)
you will find that a lot more work. If it is as is common two wires twisted
they must be seperated and then you can join the windings to run them in
parallel for the extra current. Each winding should be connected "start to
start" and "finish to finish".
If you should get it wrong there would be no output.


--
Regards ............... Rheilly Phoull
 
"RayGilbert" <raygilbert@lineone.net> wrote in message
news:5708f106.0312191702.43bd68a9@posting.google.com...
Hi,
Is there a proven method to rectify a 40-0-40 hardwired centre tapped
transformer using both of the windings for fairly high current
application.
I would prefer a method with little or no smoke and absolutely no loud
bangs :)
TIA
Raymond Gilbert
Click to expand...
It's pretty straight forward....

A full wave center tapped design will give you the 16 amps or more.
(Each half of the transformer is alternativly used at twice it's rated
current for half the time.)
Be sure to use 2 WAY over 16 amp diodes, and the voltage rating should not
be less than 200.
[The center tap is a common... Ground or power, depending on which way you
install the diodes.]

--
*
| __O Thomas C. Sefranek WA1RHP@ARRL.net
|_-\<,_ Amateur Radio Operator: WA1RHP
(*)/ (*) Bicycle mobile on 145.41, 448.625 MHz

http://hamradio.cmcorp.com/inventory/Inventory.html
http://www.harvardrepeater.org
 
Thanks for your reply Rheilly,
I don't think that the windings can easily be accessed as it is a
sealed toroidal transformer.
Kind regards
Raymond Gilbert

"Rheilly Phoull" <shredder@bigpong.net> wrote in message news:<3fe43853$0$1756$5a62ac22@freenews.iinet.net.au>...
"RayGilbert" <raygilbert@lineone.net> wrote in message
news:5708f106.0312191702.43bd68a9@posting.google.com...
Hi,
Is there a proven method to rectify a 40-0-40 hardwired centre tapped
transformer using both of the windings for fairly high current
application.
I would prefer a method with little or no smoke and absolutely no loud
bangs :)
TIA
Raymond Gilbert

You will have to find a way to seperate the two windings, ie the centre tap.
If the outcoming center tap is just one cable (Not two wires twisted etc)
you will find that a lot more work. If it is as is common two wires twisted
they must be seperated and then you can join the windings to run them in
parallel for the extra current. Each winding should be connected "start to
start" and "finish to finish".
If you should get it wrong there would be no output.
Click to expand...
 
RayGilbert wrote:
Thanks for your reply Rheilly,
I don't think that the windings can easily be accessed as it is a
sealed toroidal transformer.
Click to expand...
Then you are stuck with DC transformation. A two phase switching buck
regulator could transform the rectified and filtered 113 volts to 40
while increasing the current from about 6 amps to 16 amps and you get
regulation and possibly current limit to boot. But it is quite a
project.

--
John Popelish
 
Thanks for your reply Thomas,
Looks promising then.
What would be the theoretical rectified voltage (peak and RMS).
Would I connnect as follows

40v > D1 anode D1 cathode > smoothing > load
0v > common (Ground)
40v > D2 anode D2 cathode > smoothing > load

cathodes connected together before smoothing.

I tried some ASCII art but I couldn't understand it myself.

Kind regards
Raymond Gilbert

"Thomas C. Sefranek" <WA1RHP@ARRL.NET> wrote in message news:<A-mdnUne0qacznmi4p2dnA@comcast.com>...
"RayGilbert" <raygilbert@lineone.net> wrote in message
news:5708f106.0312191702.43bd68a9@posting.google.com...
Hi,
Is there a proven method to rectify a 40-0-40 hardwired centre tapped
transformer using both of the windings for fairly high current
application.
I would prefer a method with little or no smoke and absolutely no loud
bangs :)
TIA
Raymond Gilbert

It's pretty straight forward....

A full wave center tapped design will give you the 16 amps or more.
(Each half of the transformer is alternativly used at twice it's rated
current for half the time.)
Be sure to use 2 WAY over 16 amp diodes, and the voltage rating should not
be less than 200.
[The center tap is a common... Ground or power, depending on which way you
install the diodes.]
Click to expand...
 
RayGilbert wrote:
Thanks for your reply Thomas,
Looks promising then.
What would be the theoretical rectified voltage (peak and RMS).
Would I connnect as follows

40v > D1 anode D1 cathode > smoothing > load
0v > common (Ground)
40v > D2 anode D2 cathode > smoothing > load

cathodes connected together before smoothing.
Click to expand...

Low down this page: http://www.plitron.com/Pages/technote.htm


"Thomas C. Sefranek" <WA1RHP@ARRL.NET> wrote in message news:<A-
mdnUne0qacznmi4p2dnA@comcast.com>...
"RayGilbert" <raygilbert@lineone.net> wrote in message
news:5708f106.0312191702.43bd68a9@posting.google.com...
Hi,
Is there a proven method to rectify a 40-0-40 hardwired centre
tapped transformer using both of the windings for fairly high
current application.

A full wave center tapped design will give you the 16 amps or more.
Click to expand...
 
"RayGilbert" <raygilbert@lineone.net> wrote in message
news:5708f106.0312201117.7e7cd1ea@posting.google.com...
Thanks for your reply Thomas,
Looks promising then.
What would be the theoretical rectified voltage (peak and RMS).
Click to expand...
It all depends on your load and "smoothing" capacitor values.

Peak voltage is roughly 1.4 times the RMS value of the transformer.
So unloaded you could see greater than 56 volts.
Adding load will lower the voltage until at 16 amps or so it will be 40 VDC.
It is NOT a regulated voltage.

Would I connnect as follows

40v > D1 anode D1 cathode > smoothing > load
0v > common (Ground)
40v > D2 anode D2 cathode > smoothing > load

cathodes connected together before smoothing.
Click to expand...
Yes.
Kind regards
Raymond Gilbert
Click to expand...

--
*
| __O Thomas C. Sefranek WA1RHP@ARRL.net
|_-\<,_ Amateur Radio Operator: WA1RHP
(*)/ (*) Bicycle mobile on 145.41, 448.625 MHz

http://hamradio.cmcorp.com/inventory/Inventory.html
http://www.harvardrepeater.org
 
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