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rectifier
------A total SNIP of everything and on to a better idea.-------
Consider using avalanche rectifiers and it makes all the stuff about the caps and resistors a mute point. There are some good application notes out there on this subject and the whys and wherefores of it all. For your needs the BYM36E might be a good choice. At around 30 cents a piece hard to beat. http://www.alliedelec.com/Search/Sea...61EC8009E6617F Best of luck in your project! Regards, Paul GregS wrote: I am having some difficulty finding a bridge rectifier of 3 Kv and 3 amps. ?? thanks greg N6GS |
#2
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rectifier
Paul E. Cater wrote:
------A total SNIP of everything and on to a better idea.------- Consider using avalanche rectifiers and it makes all the stuff about the caps and resistors a mute point. There are some good application notes out there on this subject and the whys and wherefores of it all. For your needs the BYM36E might be a good choice. At around 30 cents a piece hard to beat. http://www.alliedelec.com/Search/Sea...61EC8009E6617F Best of luck in your project! Regards, Paul GregS wrote: I am having some difficulty finding a bridge rectifier of 3 Kv and 3 amps. ?? thanks greg N6GS I perused the datasheets of both the BYM36E and 1N5408. Of the specifications that could matter (that differed): Reverse Current: 1N5408 = 5uA @ 25°C Ta, 500uA @ 100°C Ta BYM36E = 5uA @ 25°C Tj, 100uA @ 150°C Tj Reverse Recovery Time: 1N5408 = Not Rated BYM36E = 150ns Nonrepetitive Peak Forward Surge Current: 1N5408 = 200A BYM36E = 65A While the BYM36E shows better Reverse Current figures at elevated temperature (and the measurement point isn't the same), I think it unlikely that the OP is going to operate them at such temperatures. Considering the application is 50/60Hz (Period = 20/16.6 ms), Reverse Recovery Time is not a factor. However, when it comes to Nonrepetitive Peak Forward Surge Current, the 1N5408 is clearly better. Allied shows 23 hits for 1N5408, the least expensive being $0.092 each in 1-24 piece lots (stk #568-0554). Bryan |
#3
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rectifier
Bryan wrote:
Paul E. Cater wrote: ------A total SNIP of everything and on to a better idea.------- Consider using avalanche rectifiers and it makes all the stuff about the caps and resistors a mute point. There are some good application notes out there on this subject and the whys and wherefores of it all. For your needs the BYM36E might be a good choice. At around 30 cents a piece hard to beat. http://www.alliedelec.com/Search/Sea...61EC8009E6617F Best of luck in your project! Regards, Paul GregS wrote: I am having some difficulty finding a bridge rectifier of 3 Kv and 3 amps. ?? thanks greg N6GS I perused the datasheets of both the BYM36E and 1N5408. Of the specifications that could matter (that differed): Reverse Current: 1N5408 = 5uA @ 25°C Ta, 500uA @ 100°C Ta BYM36E = 5uA @ 25°C Tj, 100uA @ 150°C Tj Reverse Recovery Time: 1N5408 = Not Rated BYM36E = 150ns Nonrepetitive Peak Forward Surge Current: 1N5408 = 200A BYM36E = 65A While the BYM36E shows better Reverse Current figures at elevated temperature (and the measurement point isn't the same), I think it unlikely that the OP is going to operate them at such temperatures. Considering the application is 50/60Hz (Period = 20/16.6 ms), Reverse Recovery Time is not a factor. However, when it comes to Nonrepetitive Peak Forward Surge Current, the 1N5408 is clearly better. Allied shows 23 hits for 1N5408, the least expensive being $0.092 each in 1-24 piece lots (stk #568-0554). Bryan Good day all, There are other factors that make avalanche rectifiers a good choice over standard types. Of course he should not exceed the specifications on the data sheets for either. Comparing apples to oranges here and overlooking the advantages of the basic behaviors of an avalanche device in an application that can be plagued with spikes. Here is a couple references on the subject. There are many more out and about. http://www.dynexsemi.com/assets/DNX_AN5370_Jul02.pdf http://www.highvoltageconnection.com...che-diodes.htm The "non-snappy" behavior, minimizes circuit ringing and can reduce RFI too! They are rugged and able to withstand reverse energy much better than conventional diodes. If the OP was actually thinking of using resistors and caps as has been batted around relentlessly in this group and others, and when compared to other avalanche class devices, the .30 cents is a good price. I have no doubt that if he decides to slap in 5408's with or without all the extra stuff, it will give him years of service taking for granted he has the PIV and "I" requirements properly. I simply wanted to offer him an alternative that eliminates the compensation network argument and adds another layer of protection. Best regards to all, Paul WD8OSU It is up to him as to how he wants to approach and remedy his situation. He is the engineer on the project. |
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