Re: [CAD_CAM_EDM_DRO] Re: capacitor

mariss92705 wrote:

> Jon,
>
> Good points except for the cap size which is a bit of an over-kill. I
> suggest using the following for sizing caps:
>
> For 60Hz, C = (80,000 times I) / V
> For 50Hz, C = (100,000 times I) / V
>
> Where V is the power supply voltage, I is the maximum power supply
> current and the answer, C, is in microfarads.
>
> This scales the ripple voltage to about 10% of the output voltage and
> keeps the power factor reasonable.
>
> For 10A @ 80VDC, this yeilds 10,000 uF at 60Hz.

Well, maybe I'm thinking of Servo power supplies, but I use a MUCH bigger
cap than that in my power supply. But, then, a servo can really draw
substantial current surges. Also, unless you have a braking resistor
and control circuitry, you need enough energy storage to prevent the
DC bus from surging during motor deceleration.

Jon