Skribent: Narcis Garcia Dato: Til: dng Emne: Re: [DNG] An alternative to renaming [was Re: Proposed change in
behaviour for ascii: eudev net.ifnames]
El 24/08/17 a les 11:33, Edward Bartolo ha escrit: > Quote by Karl Hammar: "There are several drawback useing the old
> transformer + rectifier design. Of main consern is the current spikes
> seen on the power grid when the diodes starts to conduct. Your power
> supplier don't like them and that is why we have PFC to make the unit
> behave more like a resistor to the power grid."
>
> If PFC stands for Power Factor Correction, using a switching power
> supply doesn't free one from using rectification of the mains to power
> the switching transistors. The rectifier diodes will also have current
> spikes and we are essentially back to square one. With 3 phase power
> rectification the current spikes can be greatly reduced as the
> rectified voltage output from the rectifier without a smoothing
> capacitor never goes below ~85% of peak.
>
> If voltage rectification was such a problem, all devices/appliances
> that have to use a DC voltage source would be at blame, which is
> clearly not the case. Power Factor Correction enters the equation when
> loads having a substantial inductive component exist. This is the case
> when certain types of motors are used. Three phase motors do not
> produce a significant inductive load if they are well designed. This
> is also true of transformers given their primaries are well designed
> to keep the magnetising currents at a minimum.
>
> For voltage rectification Power Factor Correction (PFC) is not an
> issue. If this is a new issue that older text books about
> electricity/electronics did not discuss, please direct me to your
> sources of information.
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Re: [DNG] An alternative to renamin…
