30 Amp --- A little too High for me ! I would use 25 Amp. WA6VAB Ray K3
From: Dave Sent: Wednesday, July 21, 2021 7:43 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] In Line Power Pole Fuses Hi, I am unsure what you are asking... If you are asking about fuse values, I select values a bit above the max peak current I expect. For my K3 I use a 30 amp fuse. If you are asking about voltage drop, and want to know what the K3 sees, there is a built in volt meter in the K3, (see the manual), which will show you the voltage at the K3, after all your fusing, and wiring. I always take my voltage readings at full output. I try and stay within the limits Elecraft sets for voltage. If I am running low voltage on transmit, I goose the power supply slightly, staying below the max voltage rating Elecraft recommends when not transmitting at full power. The fuse(s) is/are probably not going to protect my radio-- if something happens, (i.e., current draw in excess of 30 amps), the radio is probably already broken. I use the fuse to reduce runaway thermal effects, (read that as fire), on my power supply wiring in the event of a short to ground. I place the fuse(s) as close to the power supply as my wiring will allow. 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist, RFI ARRL Asst. Director, NW Division, Technical Resources On 7/21/21 7:18 PM, Peder Kittelson wrote: > I have fused my Elecraft radio equipment with inline power pole positive > and negative ATC car standard blade fuses. > I am now doing an audit of the fuses in my system to make sure they are > appropriate for the equipment they protect. I realize there are internal > fuses in many cases, I prefer doubling my protection with inline external > fuses as well. > > I have not read or heard anyone discuss the appropriate amperage ratings of > fuses for my equipment or equipment in general. I would appreciate your > recommendations on fuse sizes for these, as well as general approaches. > > Equipment and Specifications from Elecraft Manuals: > > 1. Elecraft K3s with 100 watt amp: Specs are 17-22 amps typical on > transmit, recommended 25 amp power supply. > > 2. Elecraft KPA 500: Specs are PA Current 20 amp maximum. > > 3. Elecraft KX3: Specs are 1-2 amp typical current in transmit. > > One other important question. I have conquered much of the RFI in my radio > room using power poles with extended thick Red and Black wiring wound > around toroids. In this case the leads go from the Astron RS-35A to the > K3s. I want to make sure there isn't too much drop in voltage over the > extended toroid wiring. How can I best gauge what the K3s receives in this > setup? The manual says it should receive 13.8 volts nominal, 11 volts > minimum and 15 volts maximum. I think I am beyond the provided and > recommended 5' power cable. I have not had any problems (that I know of). > > I do not have a desk full of electronic devices for evaluating this, so is > there a simple way to be reasonably sure? > > 73 and thanks for your help, > > W7RPK, Peder > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to d...@nk7z.net > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to wa6...@gmail.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
