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Re: DC Filter Choke on low voltage power supplies

Posted by Don Wilhelm-4 on Feb 05, 2012; 6:56pm
URL: http://elecraft.85.s1.nabble.com/DC-Filter-Choke-on-low-voltage-power-supplies-tp7256286p7256418.html

Ed,

Using a large filter choke in a relatively low voltage supply is
difficult because of the voltage drop across the choke - and that
voltage drop will change with current draw changes - so instead of
improving the regulation, it will actually worsen.  The problem is in
the size wire used to wind the choke.  In other words, a 25 volt drop at
3000 volts is a drop in the bucket, but even a 10 volt drop at 50 volts
is likely to be too much.

73,
Don W3FPR

On 2/5/2012 12:54 PM, Edward R. Cole wrote:

> Recent discussion of use of a filter choke with a battery powered K3
> prompts my question in another application.  I have a 50vdc 50amp
> switching PS which will power a 1100w sspa.  Output filtering may be
> needed to suppress switching impulses on the 50vdc output.  I have a
> large filter choke that was used in a 3000v PS which is probably at
> least 5-8Hy.  Do I need a bleeder resistor across it for protecting
> circuits when powering off the switching PS?  Or is using the large
> filter choke not a good idea at all.  What size filter chokes would
> be recommended?  The 50v PS is a HP PS intended for telephone industry (51v).
>
>
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