RadioBanter - View Single Post - 13.8V high current power supply

May 8th 06, 08:09 PM posted to rec.radio.amateur.homebrew

wrote:
Well I had another 10 minutes to spare again today so took a different
secondary tapping to try to get more voltage headroom. Following that
tweak, I now have 25.5VDC available across the large electrolytics.
This is obviously plenty enough for 13.8VDC regulated; but is it now
*too* much to drop efficiently?
==============================
25.5 V seems a normal voltage level for a regulated 13.8 V PSU , no way
too high.
Suggest you check the working voltage of the large elctrolytic
capacitors. They should be 40 V or higher.
I am currently repairing a Yaesu PSU ,output 13.8 V -20A max, having
40V electrol. caps in output of 25A bridge rectifier.
FYI the unit has a soft start facility being a 10 Ohms resistor in the
230V -AC supply circuit ; this to limit bridge rectifier inrush current,
charging the electrolytic caps from zero.
As soon as DC output (13.8V) is there, a relay will be energised ,its
contact shorting the above 10 Ohms resistor .

Frank GM0CSZ / KN6WH