| Page 1 of 2 | 1 | 2 |
|
|
Power Converter
Off topic, but you can`t power an antenna without power to the
transmitter. I`m looking for a d-c to d-c converter that takes 28 volts on the input and supplies 12 volts on the output. Up to 8 amperes may regularly be drawn from the supply. That`s about 100 watts. I need it now. That`s why I`m imposing on this group. There is no more knowledgeable group to ask that I know of. I don`t have time to build anything, though I`ve built such inverters and converters. A simple voltage divider or regulator is too lossy for high utilization. I need lossless resistance. Maybe there is an applicable aircraft converter that is surplus somewhere, or maybe there is a stock automotive item as there are such 28-volt battery systems used in some big rigs. I`m in a hurry or I would quietly do all the hunting myself and not bother anybody. I would like rugged, reliable, efficient, replaceable, and cheap. Thank you in advance for directions to the source of my d-c step-down transformer. Please excuse the misuse of this forum, but I believe it is my best resource for most things technical and unusual. Best regards, Richard Harrison, KB5WZI |
On Mon, 8 Mar 2004 15:15:55 -0600 (CST),
(Richard Harrison) wrote: I`m looking for a d-c to d-c converter that takes 28 volts on the input and supplies 12 volts on the output. Up to 8 amperes may regularly be drawn from the supply. That`s about 100 watts. Hi Richard, Try Jameco at: http://www.jameco.com/Jameco/Products/ProdDS/206041.pdf 73's Richard Clark, KB7QHC |
In article ,
Richard Harrison wrote: Off topic, but you can`t power an antenna without power to the transmitter. I`m looking for a d-c to d-c converter that takes 28 volts on the input and supplies 12 volts on the output. Up to 8 amperes may regularly be drawn from the supply. That`s about 100 watts. I need it now. That`s why I`m imposing on this group. There is no more knowledgeable group to ask that I know of. I don`t have time to build anything, though I`ve built such inverters and converters. Check with Vicor (www.vicr.com). They make a whole range of DC-to-DC converter modules. Example: their V24B12C200B converter module takes 18-36 volts in, 12 volts out (programmable from 10% to 11% of this, so you could get 13.2 out), efficiency 85%, 200 watts output. Current limit is 17 amps minimum, 19.2 amps typical. They do have a 100-watt module, but I suspect you'd be running it right at the ragged edge of its specs. There are other manufacturers playing in this market space... Datel is one. A simple voltage divider or regulator is too lossy for high utilization. I need lossless resistance. You won't get 100% efficiency out of anything like this. 80-90% seems to be achievable with commercial products. I would like rugged, reliable, efficient, replaceable, and cheap. I think you can get the first four if you look around. The fifth is likely to be the hardest, if you want the first four. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
Richard,
try looking at http://www.astroncorp.com They have two different converters like you are looking for. |
"Dave Platt" wrote in message ... In article , Richard Harrison wrote: Off topic, but you can`t power an antenna without power to the transmitter. I`m looking for a d-c to d-c converter that takes 28 volts on the input and supplies 12 volts on the output. Up to 8 amperes may regularly be drawn from the supply. That`s about 100 watts. I need it now. That`s why I`m imposing on this group. There is no more knowledgeable group to ask that I know of. I don`t have time to build anything, though I`ve built such inverters and converters. Check with Vicor (www.vicr.com). They make a whole range of DC-to-DC converter modules. Example: their V24B12C200B converter module takes 18-36 volts in, 12 volts out (programmable from 10% to 11% of this, so you could get 13.2 out), efficiency 85%, 200 watts output. Current limit is 17 amps minimum, 19.2 amps typical. I suspect, since 'up to 8 amperes may be drawn', that he'll have a hard time meeting the '17 amps minimum' spec... __ Steve KI5YG .. |
In article om,
Stephen Cowell wrote: Example: their V24B12C200B converter module takes 18-36 volts in, 12 volts out (programmable from 10% to 11% of this, so you could get 13.2 out), efficiency 85%, 200 watts output. Current limit is 17 amps minimum, 19.2 amps typical. I suspect, since 'up to 8 amperes may be drawn', that he'll have a hard time meeting the '17 amps minimum' spec... Sorry, I was unclear. What the phraseology means is "The converter's maximum current output is limited to a value which might, in some cases, be as low as 17 amperes, but is typically around 19.2 amperes." I didn't mean to imply that you _must_ draw 17 amperes from the converter in order for it to work. There doesn't appear to be a significant lower limit - load reguulation is given as 0.2% typical "no load to full load, nominal input" as long as you haven't trimmed the converter to a lower output voltage. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
Sorry, I was unclear. What the phraseology means is "The converter's
maximum current output is limited to a value which might, in some cases, be as low as 17 amperes, but is typically around 19.2 amperes." I didn't mean to imply that you _must_ draw 17 amperes from the converter in order for it to work. There doesn't appear to be a significant lower limit - load reguulation is given as 0.2% typical "no load to full load, nominal input" as long as you haven't trimmed the converter to a lower output voltage. -- Dave Platt AE6EO Dave, Even though you may have been unclear, REAL radio amateurs knew exactly what you meant - ignore wise-ass comments from those trying to be a bit more clever than others - it illustrates various weaknesses ..... Nick |
"nick smith" wrote in message ... Sorry, I was unclear. What the phraseology means is "The converter's maximum current output is limited to a value which might, in some cases, be as low as 17 amperes, but is typically around 19.2 amperes." I didn't mean to imply that you _must_ draw 17 amperes from the converter in order for it to work. There doesn't appear to be a significant lower limit - load reguulation is given as 0.2% typical "no load to full load, nominal input" as long as you haven't trimmed the converter to a lower output voltage. -- Dave Platt AE6EO Dave, Even though you may have been unclear, REAL radio amateurs knew exactly what you meant - ignore wise-ass comments from those trying to be a bit more clever than others - it illustrates various weaknesses ..... Hey Nick... chupe' mis huevos. It was *not* clear, and Dave knew it, and copped to it. __ Steve KI5YG .. |
Richard,
Assuming there is a common ground, and input and output are the same polarity, what you want is called a buck converter. To roll your own, National and TI make chips. To buy a whole unit you need to go to a non hobby distributor's web site like Newark, Allied, Avnet, or Arrow. Some manufacturers of these things are Astec, Condor, Cosell, Elpac, and Lambda(expensive). Tam/WB2TT "Richard Harrison" wrote in message ... Off topic, but you can`t power an antenna without power to the transmitter. I`m looking for a d-c to d-c converter that takes 28 volts on the input and supplies 12 volts on the output. Up to 8 amperes may regularly be drawn from the supply. That`s about 100 watts. I need it now. That`s why I`m imposing on this group. There is no more knowledgeable group to ask that I know of. I don`t have time to build anything, though I`ve built such inverters and converters. A simple voltage divider or regulator is too lossy for high utilization. I need lossless resistance. Maybe there is an applicable aircraft converter that is surplus somewhere, or maybe there is a stock automotive item as there are such 28-volt battery systems used in some big rigs. I`m in a hurry or I would quietly do all the hunting myself and not bother anybody. I would like rugged, reliable, efficient, replaceable, and cheap. Thank you in advance for directions to the source of my d-c step-down transformer. Please excuse the misuse of this forum, but I believe it is my best resource for most things technical and unusual. Best regards, Richard Harrison, KB5WZI |
| All times are GMT +1. The time now is 09:36 PM. |
|
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
RadioBanter.com