Wish I had time to look into it more, but a book I have
"Industrial Electronics Handbook" by Cockrell states that
RMS ripple current should be square root of 2 for 100 percent
rectifier efficiency. With solid state diodes the efficiency
should be near 100% for a high voltage power supply. The interesting
point is that for lower efficiencies the factor is less than 1.4.
So it seems that 1.4 times the DC out is the max.
73
Bill wa4lav
At 09:18 AM 3/8/99 -0000, you wrote:
>
>Steve says:
>
>>The rms and peak currents depend on the ratio of source and load
>>resistances and the capacitor value. For a decent high power PSU (bridge
>>with capacitor input) the ratio should be in the regions of 1-2% maximum
>>and you will have enough capacitance that it doesn't affect the
>>calculation). In these circumstances an old handbook I have puts the rms
>>ripple at about 3x dc current, and peak ripple at about 12x dc while a
>>spice simulation gives values of about 2x and 8x respectively.
>
>For what it's worth, many years ago, I did some measurements using a
>thermo-ammeter, and found that provided the capacitor was big enough to give
>negligible voltage drop on load, the measured ripple current was 1.4 times
>the DC. That was for bridge rectifiers. Being a thermo-ammeter, that should
>be the rms.
>
>73
>
>Peter G3RZP
>
>
>
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>
William L. Fuqua III P.E. E-mail WLFUQU00@POP.UKY.EDU Phone (606) 257-4155
Department of Physics and Astronomy CP-177 Chem. Phys. Bldg.
University of Kentucky , Lexington, Ky 40506-0055
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