On Sun, 30 Jun 2002 10:27:09 +1000 "David Smith" <vk3hz@wia.org.au>
writes:
> Turns out that this capacitor is from an HP defibrulator.
>
> There seems to be a question about whether a defib cap can handle
> continuous
> PSU filter duty. It may need to be derated.
>
> Any comments?
>
> Regards,
> David Smith
> VK3HZ
>
Hi David,
Maxwell manufactures both pulse discharge and continuous rated filter
capacitors. The type is usually marked on the label unless the part was
made special for a customer.
Hewlett Packard may have well spec'ed a continuous rated capacitor to
provide some extra margin against failures (and lawsuits!) in that
medical application.
Maxwell pulse rated caps can be safely operated at 2/3 of their marked
voltage in filter applications -- their life expectancy equals a
continuous rated cap at that point.
73,
Marv WC6W
>
> > From: "David Smith" <vk3hz@wia.org.au>
> > To: <amps@contesting.com>
To: <amps@contesting.com>
> > Date: Sat, 29 Jun 2002 21:31:34 +1000
> > Subject: [Amps] Filter Capacitors - Oil Filled vs. Electrolytic
> >
> > I'm on to building the HV PSU for the 8877.
> >
> > I have 2 alternatives for filtering - a used but good 54uF 4.2kV
> oil-filled
> > Maxwell or a string of 10 new 470uF 450V electrolytics (with 45K
> 10W
> > equalisers). They work out to roughly the same cost.
> >
> > I'm tending towards the oil-filled cap because it simplifies
> construction.
> > Any comments on either? I've seen comments here regarding
> equalising
> > electro strings and also read things about forming them. Do
> oil-filled
> caps
> > go off over time? Is it OK to mount them on their side?
> >
> > Regards,
> > David Smith
> > VK3HZ
>
>
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>
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