Don and all: Don is right, but I think that the situation is even worse than Don describes. The power supply for a tube-type rig need only generate up to a few Amps, not the 40 or 50 Amps that you might need for a big solid-state rig. An inductor on the order of several Henrys and rated for several tens of Amps would be impractically HUGE (and hideously expensive) for table-top gear.
73, Steve AA4AK On 2/5/2012 1:56 PM, Don Wilhelm wrote: > 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). >> >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
