Triac switch would do it. Seems like a natural for equipment but seldom used.
Chuck Jack KE9UW Sent from my iPhone, cjack > On Jun 27, 2018, at 2:54 PM, Bob McGraw K4TAX <rmcg...@blomand.net> wrote: > > Yes that is the magnetization current of the transformer core. > Doesn't happen when powered up at the zero voltage crossing point. > > One person advised to always turn on equipment at the zero crossing point. > Seems like a good idea. Now if I could only get my finger timed correctly to > do this. > > Bob, K4TAX > > > Sent from my iPhone > >> On Jun 27, 2018, at 2:42 PM, hawley, charles j jr <c-haw...@illinois.edu> >> wrote: >> >> I’ve only noticed a thump with a piece of equipment which has a power supply >> when it turns on at a line voltage peak. On the occasion that it turns on at >> a line voltage zero crossing, it makes no noise at all. >> >> Chuck >> KE9UW >> >> Sent from my iPhone, cjack >> >>> On Jun 27, 2018, at 2:10 PM, Bob McGraw K4TAX <rmcg...@blomand.net> wrote: >>> >>> Seems that the AC line supplying the equipment has a rather high impedance >>> thus allowing the voltage to suddenly drop under the dynamic load and then >>> surge to a higher than normal value. >>> >>> A dedicated 120V and/or 240V service should be considered for the station >>> power. >>> >>> Laser printers do draw considerable power when they start. >>> >>> Bob, K4TAX >>> >>> >>> Sent from my iPhone >>> >>>> On Jun 27, 2018, at 2:00 PM, John Simmons <jasimm...@pinewooddata.com> >>>> wrote: >>>> >>>> My Astron RS35 does the same thing under the same conditions. >>>> >>>> -John NI0K >>>> >>>> Matt NQ6N wrote on 6/27/2018 1:20 PM: >>>>> My KPA500 makes a noticeable hum/thump when the laser printer that is on >>>>> the same circuit draws a lot of current. >>>>> >>>>> 73, >>>>> Matt NQ6N >>>>> >>>>> On Wed, Jun 27, 2018 at 12:58 PM Jim Brown <j...@audiosystemsgroup.com> >>>>> wrote: >>>>> >>>>>>> On 6/27/2018 10:37 AM, Richard Wade wrote: >>>>>>> If I had to venture a guess, I would say that somehow the unpowered >>>>>> KPA500 >>>>>>> was picking up noise on the shack wiring. Very strange. Is that >>>>>> possible?? >>>>>> >>>>>> It is if equipment in your shack is not properly bonded together, and to >>>>>> house grounds that are also properly bonded together. Study N0AX's >>>>>> recent ARRL book on the topic, to which I contributed, or the slides for >>>>>> a tutorial talk I've done at several hamfests. >>>>>> >>>>>> http://k9yc.com/GroundingAndAudio.pdf >>>>>> >>>>>> 73, Jim K9YC >>>>>> >>>>>> >>>>>> ______________________________________________________________ >>>>>> 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 m...@nq6n.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 jasimm...@pinewooddata.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 rmcg...@blomand.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 c-haw...@illinois.edu >> > > ______________________________________________________________ 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
