Can I use 4 scr's as a ordinary rectifier bridge ?
Bookmark this page:
 Yahoo!
 Google
 Windows Live
 del.icio.us
 digg
 Netscape
|
|
||||||||||||||||
|
Posted by Ray on February 16, 2008, 2:28 pm
Please log in for more thread options I would like to use 4 of them to make an ordinary bridge rectifier for a heavy duty 12-15 vdc power supply... What do i do with the gate, and the other wire sticking out of the scr ? When these are connected, do I gave an 80 amp bridge, or a 160 amp bridge ? I have read arguments about this, havent heard a definite conclusion...(Is each diode only in use half the time ? m | ||||||||||||||||
|
Posted by Phil Allison on February 16, 2008, 6:49 pm
Please log in for more thread options "Ray" ** The C46H SCR has two terminals on top of the case - the gate is the smaller and the larger is the cathode. Connect a 1 amp diode from the case ( ie anode) to the gate to convert the SCR to simple diode operation. > When these are connected, do I gave an 80 amp bridge, or a 160 amp bridge
> ? ** Neither. > I have read arguments about this, havent heard a definite conclusion...(Is
> each diode only in use half the time ? ** For a bridge feeding a capacitor input filter - each diode conducts only about 10 % of the time. Down load the pdf on this page - it has all the gory details. http://www.datasheetarchive.com/preview/959231.html Your idea will maybe create a 30 amp ( average DC current) bridge. It will need a massive heatsink too. Buy an ordinary 40 amp bridge. ...... Phil | ||||||||||||||||
|
Posted by John Popelish on February 16, 2008, 7:26 pm
Please log in for more thread options Ray wrote:
> I have a bunch of old 80 amp scr's (GE C46h) out of an old lighting dimmer
> > I would like to use 4 of them to make an ordinary bridge rectifier for a > heavy duty 12-15 vdc power supply... > > What do i do with the gate, and the other wire sticking out of the scr ? > > When these are connected, do I gave an 80 amp bridge, or a 160 amp bridge ? > > I have read arguments about this, havent heard a definite conclusion...(Is > each diode only in use half the time ? You have to figure out a way to trigger the gates each time the SCR is forward biased, but not over voltage the gate in reverse, when the SCR is reverse biased. And you will have to put up with about twice the forward voltage drop compared to normal rectifier diodes, since each SCR has two junctions in series when they are conducting. Are actual rectifier diodes so expensive? If I were building a 12 to 15 volt supply, I would use Schottky diodes and cut the forward drop about in half, compared to silicon junction diodes, and cut the waste heat. -- Regards, John Popelish | ||||||||||||||||
|
Posted by Ray on February 16, 2008, 8:25 pm
Please log in for more thread options I am looking to make an 80 amp or greater power supply, and havent found any
bridges in that category, and 100 amp diodes seem expensive and hard to find, Ray > Ray wrote:
>> I have a bunch of old 80 amp scr's (GE C46h) out of an old lighting
>> dimmer >> >> I would like to use 4 of them to make an ordinary bridge rectifier for >> a heavy duty 12-15 vdc power supply... >> >> What do i do with the gate, and the other wire sticking out of the scr ? >> >> When these are connected, do I gave an 80 amp bridge, or a 160 amp bridge >> ? >> >> I have read arguments about this, havent heard a definite >> conclusion...(Is each diode only in use half the time ? >
> You have to figure out a way to trigger the gates each time the SCR is > forward biased, but not over voltage the gate in reverse, when the SCR is > reverse biased. And you will have to put up with about twice the forward > voltage drop compared to normal rectifier diodes, since each SCR has two > junctions in series when they are conducting. > > Are actual rectifier diodes so expensive? > > If I were building a 12 to 15 volt supply, I would use Schottky diodes and > cut the forward drop about in half, compared to silicon junction diodes, > and cut the waste heat. > > -- > Regards, > > John Popelish | ||||||||||||||||
|
Posted by Phil Allison on February 16, 2008, 8:36 pm
Please log in for more thread options
"Ray" >
>I am looking to make an 80 amp or greater power supply, and havent found >any bridges in that category, ** You CAN use more than one 40 amp bridge - you know. Either wired in parallel and mounted on a common heatsink - OR and much more technically elegant, have the AC transformer wound with 2 or three *identical* secondaries. Then you only parallel the + and - terminals. ...... Phil | ||||||||||||||||
| Similar Threads | Posted |
| Can I use 4 scr's as a ordinary rectifier bridge ? | February 16, 2008, 2:28 pm |
| Bridge Rectifier Problem.......!!!!!!! | August 22, 2006, 6:17 am |
| six pulse bridge rectifier | December 9, 2007, 9:22 am |
| information about bridge rectifier | July 3, 2008, 6:52 am |
| LTspice / SwitcherCAD III and Bridge Rectifier question | March 16, 2005, 7:02 pm |
| Voltage concerns on a bridge rectifier-capacitor circuit | August 15, 2007, 2:19 am |
| Weird problem in Full wave (FW) bridge rectifier | November 21, 2007, 11:48 am |
| Full wave bridge rectifier circuit recommendations needed | April 1, 2008, 10:34 pm |
| nicad and ordinary battery | February 19, 2006, 4:41 pm |
| "ordinary" DC motor vs DC "servo" motor? | October 13, 2004, 5:12 pm |
| A little h-bridge help? | May 29, 2006, 11:07 am |
| H-bridge with Pic | November 4, 2006, 6:50 pm |
| H-bridge | January 18, 2007, 11:44 am |
| H-Bridge Contoller | January 9, 2006, 8:38 am |
| testing H-bridge | November 11, 2006, 1:49 pm |
>I have a bunch of old 80 amp scr's (GE C46h) out of an old lighting
>dimmer
>
> I would like to use 4 of them to make an ordinary bridge rectifier for a
> heavy duty 12-15 vdc power supply...
>
> What do i do with the gate, and the other wire sticking out of the scr ?