KPA1500 - adding fans
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For the heck of it brought my KPA1500 from the basement to the shack desk. Ran a test with 10 CQ’s on 6M with 1K out on FT8. By the time the CQ’s were done the amp temp was up to about 75C. The amp is set so the fan is always on at #1.
Added two 4” 110VAC fans in series to cut down the speed and noise and covered the exhaust holes on the top of the amp to extract air. Then I tried with just one 4” fan in the center running full speed. Bottom line there was virtually no difference in the top temp of the amp with these settings. I know, not very scientific. Just seeing if there would be a noticeable difference with adding fans. Time to move the amp back to the basement. I never hear my amps ☺ 73, N2TK, Tony ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Very good info Tony. Saves me the experiment. I think it also shows that
the guys at Elecraft did a good job in cooling design. Richard *W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF, W0MQU, J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ, XE2DV *Be joyful in hope, patient in affliction, faithful in prayer* On Fri, Aug 10, 2018 at 8:19 AM N2TK, Tony <[hidden email]> wrote: > For the heck of it brought my KPA1500 from the basement to the shack desk. > Ran a test with 10 CQ’s on 6M with 1K out on FT8. By the time the CQ’s were > done the amp temp was up to about 75C. The amp is set so the fan is always > on at #1. > Added two 4” 110VAC fans in series to cut down the speed and noise and > covered the exhaust holes on the top of the amp to extract air. Then I > tried with just one 4” fan in the center running full speed. Bottom line > there was virtually no difference in the top temp of the amp with these > settings. > I know, not very scientific. Just seeing if there would be a noticeable > difference with adding fans. > Time to move the amp back to the basement. I never hear my amps ☺ > 73, > N2TK, Tony > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by N2TK
My KPA1500 is S/N 00059. I don't operate full power all the time. I live in a
compromised antenna area, and so I will use the amp as required to make contacts that are difficult assuming I can hear the station well enough to have the QSO. I have not had problems with the weird display issue that has been reported, and also someone recently replaced their antenna tuner to solve a problem which I have not seen either yet. Thanks for this site, as it gives us a heads up if we would have similar issues with our equipment. Maybe I don't run the amp hard enough, my antenna will take 1500 watts, but I probably never push it that hard for long periods. I run FT8, but with 100 watts or less and I have made plenty of contacts. FT8 is whole another discussion. SSB is the least difficult for the amp to deal with. CW is harder and RTTY, FM,FT8 and AM are the worst. The fans on the power supply make some noise, but I have had several tube amps over the last 40 years that are louder. I haven't installed the latest software update issued in July, so I need to see if that makes any difference. I was involved with the design specification, and purchase of medium and high voltage transformers for my career. Cooling of electrical equipment is a little more complex than just installing fans. There are proper air flow requirements to look at in the design, so the air doesn't get short circuited, and actually hurt the process. So more air isn't always better if it is not properly applied. Transformers have RTD's or Thermocouples imbedded in the windings to measure transformer temperature, because that is the "hottest spot" of any transformer. The hot spot temperature is made up of the ambient air temperature normally 40 C maximum is used with a 30C average over a 24 hour period, and the temperature rise of the unit under load. Most electrical equipment design is based on a 40C maximum ambient but I didn't see in the manual what Elecraft considered for a maximum. Regardless, the ambient heat around the amplifier must be controlled and not trapped around the unit. An air conditioned space or proper ventilating for area is critical. If you don't remove the heat your unit will work harder and could make more noise than other units. Wayne or Eric can comment, but RF amplifiers must follow similar laws of physics. The heat sink temperature must be maintained or the devices primarily the LDMOS final amp units will fail. There are average and maximums I would assume are used in the Elecraft design. Ambient air must be kept at a certain maximum and air flows must not be restricted. At this time, it good to provide feedback to the vendor on operational concerns of the equipment, and I did plenty of that over the years. However, I usually realized there were some people, who did this for a living, and I was a consumer maybe a smart consumer, but still I didn't design transformers as my main employment. With all the KPA1500's still under warranty I don't think it is a good idea to modify or change anything with regards to the operation, and design of the KPA1500. Again, I am not Wayne or Eric, but I think you are doing it at your risk. I will wait for Wayne and Eric to come out with improvements, and updates based on customer and other inputs, but I will not modify the KPA1500 in anyway including external programs that change the operation without the supplier approval. I guess after the warranty period anyone can do what they want, but don't expect the supplier to honor any warranty issues that may have been created due to prior modifications of operation. Just as with a transformer, cooling of an RF amplifier is critical to the proper operation and long term reliability and life of the unit. Heat is the main cause of failure of any electrical equipment! Bill, K8ZCT -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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This is an excellent post, and I agree with all of it.
I will add that acoustic considerations also STRONGLY affect the noise produced in any ventilation system, and it is science more than an art. The engineers who specialize in this field are called acoustic consultants, their formal training is in physics and mechanical engineering, and the acoustics specialization begins at the Masters Degree level. In my professional life (I'm long retired) I worked with professionals in this discipline in the design of sound systems and acoustics for large public spaces, where one of their concerns was making very good HVAC systems so quiet that they could not be heard in concert halls. The considerations there are same as in the KPA1500 -- the turbulence (or lack thereof) of air flow, the path, air speed, the fans themselves, vibration isolation. I do NOT recommend that users experiment with ventilation. I DO strongly urge Elecraft to retain the services of a good acoustic consultant to address complaints I've seen about fan noise. 73, Jim K9YC On 8/10/2018 10:52 AM, K8ZCT wrote: > My KPA1500 is S/N 00059. I don't operate full power all the time. I live in a > compromised antenna > area, and so I will use the amp as required to make contacts that are > difficult assuming I can hear the station well enough to have the QSO. > > I have not had problems with the weird display issue that has been reported, > and also someone recently replaced their antenna tuner to solve a problem > which I have not seen either yet. Thanks for this site, as it gives us a > heads up if we would have similar issues with our equipment. > > Maybe I don't run the amp hard enough, my antenna will take 1500 watts, but > I probably never push it that hard for long periods. I run FT8, but with 100 > watts or less and I have made plenty of contacts. FT8 is whole another > discussion. SSB is the least difficult for the amp to deal with. CW is > harder and RTTY, FM,FT8 and AM are the worst. > > The fans on the power supply make some noise, but I have had several tube > amps over the last 40 years that are louder. I haven't installed the latest > software update issued in July, so I need to see if that makes any > difference. > > I was involved with the design specification, and purchase of medium and > high voltage transformers for my career. Cooling of electrical equipment is > a little more complex than just installing fans. There are proper air flow > requirements to look at in the design, so the air doesn't get short > circuited, and actually hurt the process. So more air isn't always better if > it is not properly applied. > > Transformers have RTD's or Thermocouples imbedded in the windings to measure > transformer temperature, because that is the "hottest spot" of any > transformer. The hot spot temperature is made up of the ambient air > temperature normally 40 C maximum is used with a 30C average over a 24 hour > period, and the temperature rise of the unit under load. Most electrical > equipment design is based on a 40C maximum ambient but I didn't see in the > manual what Elecraft considered for a maximum. Regardless, the ambient heat > around the amplifier must be controlled and not trapped around the unit. > An air conditioned space or proper ventilating for area is critical. If you > don't remove the heat your unit will work harder and could make more noise > than other units. > > Wayne or Eric can comment, but RF amplifiers must follow similar laws of > physics. The heat sink temperature must be maintained or the devices > primarily the LDMOS final amp units will fail. There are average and > maximums I would assume are used in the Elecraft design. Ambient air must be > kept at a certain maximum and air flows must not be restricted. > > At this time, it good to provide feedback to the vendor on operational > concerns of the equipment, and I did plenty of that over the years. However, > I usually realized there were some people, who did this for a living, and I > was a consumer maybe a smart consumer, but still I didn't design > transformers as my main employment. > > With all the KPA1500's still under warranty I don't think it is a good idea > to modify or change anything with regards to the operation, and design of > the KPA1500. Again, I am not Wayne or Eric, but I think you are doing it at > your risk. > > I will wait for Wayne and Eric to come out with improvements, and updates > based on customer and other inputs, but I will not modify the KPA1500 in > anyway including external programs that change the operation without the > supplier approval. I guess after the warranty period anyone can do what they > want, but don't expect the supplier to honor any warranty issues that may > have been created due to prior modifications of operation. > > Just as with a transformer, cooling of an RF amplifier is critical to the > proper operation and long term reliability and life of the unit. Heat is the > main cause of failure of any electrical equipment! > > > Bill, K8ZCT > > > > > > > -- > Sent from: http://elecraft.365791.n2.nabble.com/ > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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The kind of noise the amp makes is related to but a separate issue to
the loudness. Last night I was doing some comparison listening while trying to find some DX on 20m and noticed that while the FAN2 setting was definitely louder than FAN1, it seems a more "pleasant" noise compared to FAN1 which tends to have some sort of a sequel-type note to the sound it makes. 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com On 10-Aug-18 1:26 PM, Jim Brown wrote: > This is an excellent post, and I agree with all of it. > > I will add that acoustic considerations also STRONGLY affect the noise > produced in any ventilation system, and it is science more than an > art. The engineers who specialize in this field are called acoustic > consultants, their formal training is in physics and mechanical > engineering, and the acoustics specialization begins at the Masters > Degree level. In my professional life (I'm long retired) I worked with > professionals in this discipline in the design of sound systems and > acoustics for large public spaces, where one of their concerns was > making very good HVAC systems so quiet that they could not be heard in > concert halls. The considerations there are same as in the KPA1500 -- > the turbulence (or lack thereof) of air flow, the path, air speed, the > fans themselves, vibration isolation. > > I do NOT recommend that users experiment with ventilation. I DO > strongly urge Elecraft to retain the services of a good acoustic > consultant to address complaints I've seen about fan noise. > > 73, Jim K9YC > > > > On 8/10/2018 10:52 AM, K8ZCT wrote: >> My KPA1500 is S/N 00059. I don't operate full power all the time. I >> live in a >> compromised antenna >> area, and so I will use the amp as required to make contacts that are >> difficult assuming I can hear the station well enough to have the QSO. >> >> I have not had problems with the weird display issue that has been >> reported, >> and also someone recently replaced their antenna tuner to solve a >> problem >> which I have not seen either yet. Thanks for this site, as it gives us a >> heads up if we would have similar issues with our equipment. >> >> Maybe I don't run the amp hard enough, my antenna will take 1500 >> watts, but >> I probably never push it that hard for long periods. I run FT8, but >> with 100 >> watts or less and I have made plenty of contacts. FT8 is whole another >> discussion. SSB is the least difficult for the amp to deal with. CW is >> harder and RTTY, FM,FT8 and AM are the worst. >> >> The fans on the power supply make some noise, but I have had several >> tube >> amps over the last 40 years that are louder. I haven't installed the >> latest >> software update issued in July, so I need to see if that makes any >> difference. >> >> I was involved with the design specification, and purchase of medium and >> high voltage transformers for my career. Cooling of electrical >> equipment is >> a little more complex than just installing fans. There are proper air >> flow >> requirements to look at in the design, so the air doesn't get short >> circuited, and actually hurt the process. So more air isn't always >> better if >> it is not properly applied. >> >> Transformers have RTD's or Thermocouples imbedded in the windings to >> measure >> transformer temperature, because that is the "hottest spot" of any >> transformer. The hot spot temperature is made up of the ambient air >> temperature normally 40 C maximum is used with a 30C average over a >> 24 hour >> period, and the temperature rise of the unit under load. Most electrical >> equipment design is based on a 40C maximum ambient but I didn't see >> in the >> manual what Elecraft considered for a maximum. Regardless, the >> ambient heat >> around the amplifier must be controlled and not trapped around the unit. >> An air conditioned space or proper ventilating for area is critical. >> If you >> don't remove the heat your unit will work harder and could make more >> noise >> than other units. >> >> Wayne or Eric can comment, but RF amplifiers must follow similar laws of >> physics. The heat sink temperature must be maintained or the devices >> primarily the LDMOS final amp units will fail. There are average and >> maximums I would assume are used in the Elecraft design. Ambient air >> must be >> kept at a certain maximum and air flows must not be restricted. >> >> At this time, it good to provide feedback to the vendor on operational >> concerns of the equipment, and I did plenty of that over the years. >> However, >> I usually realized there were some people, who did this for a living, >> and I >> was a consumer maybe a smart consumer, but still I didn't design >> transformers as my main employment. >> >> With all the KPA1500's still under warranty I don't think it is a >> good idea >> to modify or change anything with regards to the operation, and >> design of >> the KPA1500. Again, I am not Wayne or Eric, but I think you are doing >> it at >> your risk. >> >> I will wait for Wayne and Eric to come out with improvements, and >> updates >> based on customer and other inputs, but I will not modify the KPA1500 in >> anyway including external programs that change the operation without the >> supplier approval. I guess after the warranty period anyone can do >> what they >> want, but don't expect the supplier to honor any warranty issues that >> may >> have been created due to prior modifications of operation. >> >> Just as with a transformer, cooling of an RF amplifier is critical to >> the >> proper operation and long term reliability and life of the unit. Heat >> is the >> main cause of failure of any electrical equipment! >> >> >> Bill, K8ZCT >> >> >> >> >> >> >> -- >> Sent from: http://elecraft.365791.n2.nabble.com/ >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] >> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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