raycenteno Posted September 13, 2005 Report Share Posted September 13, 2005 Hello,I am working on a project that requires dc volts. Currently my power supply generator is 30vac @ 32 amps. I would like to know if there is a way that I can transform the 30vac to 30vdc and keep the 32amp range. I would appreciate the help from anyone that can offer it. PS. I have not worked with circuits since i was in junior high school (very long time ago), I suppose that once I can refresh my memory, it should get easier. Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted September 13, 2005 Report Share Posted September 13, 2005 To do this with this efficiency you'll need to build a switch mode power supply which will be noisy and they're not the easiest things to build either, what do you wish to power with your power supply? Quote Link to comment Share on other sites More sharing options...
ante Posted September 13, 2005 Report Share Posted September 13, 2005 Hi raycenteno,Welcome to our forum.It’s not possible to put in 960W AC and get 960W DC at the other end! Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted September 13, 2005 Report Share Posted September 13, 2005 Ante,You're right but we can get to 90% efficiency these days without too much of a problem, you might put 960W in and get 864W out. ;D Quote Link to comment Share on other sites More sharing options...
ante Posted September 13, 2005 Report Share Posted September 13, 2005 Hi Alun,Well, Ray wanted to keep the 32A on the secondary side and this is not possible unless he settles for a lower voltage! Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted September 13, 2005 Report Share Posted September 13, 2005 True, there's always some loss in any system. Quote Link to comment Share on other sites More sharing options...
ante Posted September 13, 2005 Report Share Posted September 13, 2005 I think even 90% efficiency is a bit optimistic. Just putting a rectifier on a transformer will be a hard one to reach 90%! 8) Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted September 13, 2005 Report Share Posted September 13, 2005 That's funny I calculated with a rectifier to be for 30Vin @ 32A:Vout = 30 * 1.414 - 1.4 = 41.026VIout = 32 / 1.414 = 22.627APout = 928.295WEfficiency = 928.295 / 960 * 100% = 96.697%This could be improved by using high performance ultra low voltage drop schotky diodes for the rectifier.If we assume 90% for DC-DC conversion in this example the total efficency will be:0.96697 * 0.9 *100% = 87.03%However if you used the best componants money could buy DC-DC is 95% efficent so:0.96697 * 0.95 *100% = 91.86%Having said all of this you're right I'd expect about 80% efficiency for this whole circuit using normal cheap and nasty componats. ;D Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 14, 2005 Report Share Posted September 14, 2005 Vout = 30 * 1.414 Quote Link to comment Share on other sites More sharing options...
ante Posted September 14, 2005 Report Share Posted September 14, 2005 Yeah, like I said ” 90% efficiency is a bit optimistic” ;D Quote Link to comment Share on other sites More sharing options...
raycenteno Posted September 14, 2005 Author Report Share Posted September 14, 2005 thanks for the input, i do apologize for placing this question in the projects section. my goal it to have at least 90 volts and 160 amps on the end side of the power equation. I was planning to put together enough psu together in parallel and series to achieve this end volts and amps. I know it is quite a project, but I feel I can accomplish it. My goal is to power a dc motor. The motors data is 72-120vdc 130amps cont 150 amps/hr 500amp peak. I know that once i have completed my psu it should take up an area of 3'x4'. I understand that I will have some losses somewhere, but i am not sure where and how much. I was planning on using 15 psu's, me being optomistic and little experience, i was hoping to get the 90vdc @160amps. I greatly welcome your design, ideas, help, and suggestions. As well as info on what components you guys would recommend for my build, ie capacitors rectifiers and diodes. Quote Link to comment Share on other sites More sharing options...
audioguru Posted September 14, 2005 Report Share Posted September 14, 2005 My goal it to have at least 90 volts and 160 amps on the end side of the power equation.That is 14.4kW! You said your power supply generator is 30vac @ 32 amps, which is only 960W. Will you use more than 15 generators to power it all? Quote Link to comment Share on other sites More sharing options...
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