Re: resistor
Posted by
mariss92705
on 2002-07-14 11:38:48 UTC
Hugo,
That resistor carries current for only 1/2 sec or so. For that period
of time it can dissipate 500W or more. Figure on it carrying 7A so
make it 10 ohms. Important: use a wire-wound resistor only. Anything
else will vaporize.
Mariss
That resistor carries current for only 1/2 sec or so. For that period
of time it can dissipate 500W or more. Figure on it carrying 7A so
make it 10 ohms. Important: use a wire-wound resistor only. Anything
else will vaporize.
Mariss
--- In CAD_CAM_EDM_DRO@y..., "hugo_cnc" <Hwatering@h...> wrote:
> Hi all
>
> I want to build a mariss's power suplly energy dump circuit (a
mouth
> full). I'm not sure how big the resistor must be (R7). I made a
small
> calculation and I was wondering if it's somewhat right.
> The resistor can be 20 watt one. I use 70 Volt power supply so the
> current is I=P/U so 20/70= 0.29A. Therefore the resistor must be
> something like R=U/I so 70/0.29=245 ohm. Is this right or am I
miles
> of.
> Thanks
>
> Hugo