Astron is very specific about what ICS (Intermittent Communications Service) means: 50% duty cycle, 5 min on and 5 min off. The limit is almost all about keeping the regulators working within their design temperature.
Astron's typical ICS rating is about 25% higher than the continuous duty rating. For example a 20 amp Astron is rated at 20 amps ICS and 16 amps continuous. That continuous is really continuous. That is, you can demand 16 amps from it 24/7 for year after year and expect reliable operation. I've worked with many hundreds of them in commercial service and can count the number of failures on the fingers of one hand. Note that a very large number of Astron supplies are used with equipment, such as FM communications radios and repeaters, that are keyed for a while demanding a full 20 A current and then switch to receive mode for a while. Our HF Ham rigs typically have a much smaller duty cycle than specified by the ICS rating. While someone might yack on SSB or carry on sending CW for longer than five minutes, our rigs are not pulling full current except on the occasional voice peaks or when the CW key is actually closed. The average current is much, much lower than the peak. Although Elecraft recommends a 30 amp supply, I have an Astron 20A (linear) supply that has run my K3 at full power for over three years now. Under most conditions the peak current demand is under 20 Amps at 100 watts output "key down" CW, but even when it peaks at over 20 amps the supply handles it easily. Ron AC7AC ______________________________________________________________ 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
