Re: [CAD_CAM_EDM_DRO] Re: Power Supply Circuit

I'm sorry guys, I've been down in London soaking up the sun and pretty
girls. Are you planning to release a pre-made power supply Mariss?

John H.

> Sounds good.
>
> Are you still planning to do the G298 as a kit, or just as finished
> boards?
>
> Regards,
> Tony
>
> --- 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.
>
>
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