Re: Power Supply Circuit

--- In CAD_CAM_EDM_DRO@y..., "mariss92705" <mariss92705@y...> wrote:
> Tony,
>
> Yes, I have taken that into consideration. The circuit trips 15
> milliseconds after the absense of a charge current pulse. Be it 50
or
> 60 Hz, it will trip after a single missed pulse (8.33 or 10 mS).
>
> The G298 is finished and is ready for prototype boards. Next week
our
> totally revamped website launches and the G298 is pictured there.
>
> Mariss
>
> --- In CAD_CAM_EDM_DRO@y..., Tony Jeffree <tony@j...> wrote:
> > Mariss -
> >
> > Sounds excellent.
> >
> > Presumably this circuit will work equally well with the 50Hz
mains
> > frequency this side o' the pond?
> >
> > Regards,
> > Tony
> >
> > P.S. While I remember it - what progress with the G297 (or was it
> G298)?
> >
> >
> > At 03:50 15/06/2002 +0000, you wrote:
> > >What it does is sense the 120Hz cap charge restoring current
> pulses.
> > >If these are absent, such as when the AC power is shut off or if
> the
> > >cap is being backdriven by a drive, a power MOSFET crowbars a
wire-
> > >wound power resistor across the supply. The resistor is sized so
> that
> > >it draws the full current rating of the supply thru it.
> > >
> > >A 10A, 80VDC supply filter cap would be 10,000uF for a 10%
ripple
> at
> > >max current. The crowbar resistor would be 8 Ohms, forming a time
> > >constant of 80 milli-seconds. Three time constants would be
about a
> > >1/4 second discharge time for the supply after AC power shut-off.
> > >
> > >A backdriven supply develops a voltage rise on its filter cap.
This
> > >biases the bridge rectifier off and no current flows thru it. The
> > >sense circuit again places an 8 Ohm load across the supply until
> > >rectifier current is re-established.