From: "Phil Allison"
References: <%rQP9.582$8M3.firstname.lastname@example.org> <5iv7OEA7+AE+EwkX@jmwa.demon.co.uk>
Subject: Re: 120vac fan on 220vac
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Date: Wed, 1 Jan 2003 12:03:28 +1100
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"John Woodgate" wrote in message
> I read in sci.electronics.design that Phil Allison
> wrote (in ) about '120vac
> fan on 220vac', on Tue, 31 Dec 2002:
> >"John Woodgate" wrote in message
> >> You can put a capacitor in series. Not knowing fine details of your
> >> it isn't possible to suggest a precise value. A value around 3 uF is
> >> probably needed. Ideally, you start with, say, 2 uF and increase the
> >> value until you get 110 V across the fan.
> > > The capacitor need to be> suitable for 250 V **AC** working.
> > ** The voltgae across the cap will only be 120 volts AC with a high
> >inductive impedance in series - so a standard film cap rated at 400 volts
> >will be fine - no ?
> I wouldn't recommend it, because I don't know what happens at start-up,
** What might happen, what are you worried about ?
> and the 250 V AC types tolerate the high-voltage spikes that occur on
> the mains.
** The fan's inductive reactance and series resistance would filter them
out of the cap very nicely - no ?