From: John Woodgate
Subject: Re: 120vac fan on 220vac
Date: Tue, 31 Dec 2002 08:36:38 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Tue, 31 Dec 2002 13:05:10 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
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 fan,
>> 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,
and the 250 V AC types tolerate the high-voltage spikes that occur on
the mains. 400 V caps might be used to determine the required cap value.
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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