Re: [Repeater-Builder] Re: fan timer circuit
I put two 120 volt fans in series in one cabinet. Nice and quiet with a gentle air flow. John J. Riddell wrote: Kevin, another method of slowing down an AC fan is to put a capacitor in series with the AC leads as a voltage dropping element. * A local Ham played with this idea many years ago and as I recall he started * * with a 1 Mfd paper capacitor. * * In his case he dropped the voltage to around 90 volts to the fan. * * * * 73 John VE3AMZ * * * * * * * n...@no6b.com mailto:n...@no6b.com wrote: One reason why I've dismissed using any switching on my 110 V cooling fans let them spin 24/7. I have used 220 V muffin fans on 110 V and they last for years. I put one in service in 1997, and it's still turning. Kevin
RE: [Repeater-Builder] Re: fan timer circuit
I completely agree. My thinking is that a fan that runs continuously wastes power and draws dust and dirt into the equipment. I also believe that a fan that runs only during PTT is not doing much good except on very long transmissions- when the heat of the PA has made it to the fins. It may take several minutes of key-down time before the fins start getting warm, so running the fan before then is ineffective. My practice is to fix a normally-open thermal switch to one of the heat-sink fins, using heat-sink compound for good heat transfer. I have found that a switch that closes at 122 degrees Fahrenheit (50 degrees Celsius) works best, since it opens about ten degrees lower, and provides near-ideal hysteresis. The thermal switch directly controls a small AC or DC fan that blows on the fins. Not only is this an extremely simple solution, but it ensures that the fan will run only when needed and for as long as needed. I use a Cantherm switch that Digi-Key sells under catalog number 317-1094-ND for about $7. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Sunday, December 21, 2008 9:38 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: fan timer circuit Maybe it's just me, but I've never understood the need for a special circuit to run cooling fans. I run my fans from the PTT line using a relay. I have also used a simple chassis thermostat, but prefer using PTT. I suppose you could easily use both methods so that in the event that the equipment remained too warm when PTT halts, the thermostat could keep it running longer. However, I contend that if this is happening, your fans are inadequate and not keeping up with the demand right along. Why the need to continue cooling after the QSO has ended? Just because you can? Chuck WB2EDV - Original Message - From: skipp025 skipp...@yahoo.com mailto:skipp025%40yahoo.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sunday, December 21, 2008 12:24 PM Subject: [Repeater-Builder] Re: fan timer circuit Re: fan timer circuit I've seen a number of fan delay, time on, time off circuits posted on web. The neat'o web page url I just posted here on the group has one and it might be the one you're looking for. http://www.w1ghz.org/small_proj/small_proj.htm http://www.w1ghz.org/small_proj/small_proj.htm and the fan controller information is about half way down the page with a picture and down-loadable zip file. My own personal preference is to run everything warm and even a lot higher temp than most of you would expect. In a repeater station operation only an RF PA and un-modified Astron Power Supply with an undersized heat sink might get a fan. Never a failure of a well planned installation. Some of our local start-up radio clubs throwing repeater packages in place often start out using and stay with an external RF amplifier designed for mobile operation. Sometimes the amp runs so hot you can't keep your hand on the heat sink but I've yet to see one fail. cheers, skipp
RE: [Repeater-Builder] Re: fan timer circuit
I mostly agree. My thinking is that a fan that runs continuously wastes power and draws dust and dirt into the equipment. I also believe that a fan that runs only during PTT is not doing much good except on very long transmissions- when the heat of the PA has made it to the fins. It may take several minutes of key-down time before the fins start getting warm, so running the fan before then is ineffective. My practice is to fix a normally-open thermal switch to one of the heat-sink fins, using heat-sink compound for good heat transfer. I have found that a switch that closes at 122 degrees Fahrenheit (50 degrees Celsius) works best, since it opens about ten degrees lower, and provides near-ideal hysteresis. The thermal switch directly controls a small AC or DC fan that blows on the fins. Not only is this an extremely simple solution, but it ensures that the fan will run only when needed and for as long as needed. I use a Cantherm switch that Digi-Key sells under catalog number 317-1094-ND for about $7. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Sunday, December 21, 2008 9:38 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: fan timer circuit Maybe it's just me, but I've never understood the need for a special circuit to run cooling fans. I run my fans from the PTT line using a relay. I have also used a simple chassis thermostat, but prefer using PTT. I suppose you could easily use both methods so that in the event that the equipment remained too warm when PTT halts, the thermostat could keep it running longer. However, I contend that if this is happening, your fans are inadequate and not keeping up with the demand right along. Why the need to continue cooling after the QSO has ended? Just because you can? Chuck WB2EDV - Original Message - From: skipp025 skipp...@yahoo.com mailto:skipp025%40yahoo.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Sunday, December 21, 2008 12:24 PM Subject: [Repeater-Builder] Re: fan timer circuit Re: fan timer circuit I've seen a number of fan delay, time on, time off circuits posted on web. The neat'o web page url I just posted here on the group has one and it might be the one you're looking for. http://www.w1ghz.org/small_proj/small_proj.htm http://www.w1ghz.org/small_proj/small_proj.htm and the fan controller information is about half way down the page with a picture and down-loadable zip file. My own personal preference is to run everything warm and even a lot higher temp than most of you would expect. In a repeater station operation only an RF PA and un-modified Astron Power Supply with an undersized heat sink might get a fan. Never a failure of a well planned installation. Some of our local start-up radio clubs throwing repeater packages in place often start out using and stay with an external RF amplifier designed for mobile operation. Sometimes the amp runs so hot you can't keep your hand on the heat sink but I've yet to see one fail. cheers, skipp
Re: [Repeater-Builder] Re: fan timer circuit
Perfect Joe, just what I have been looking for. tom [Original Message] From: Joe k1ike_m...@snet.net To: Repeater-Builder@yahoogroups.com Date: 12/21/2008 10:05:17 PM Subject: Re: [Repeater-Builder] Re: fan timer circuit This is a simple timer that I used on my 222 repeater. When the repeater keys up the fans come on. After no PTT activity for about 2 minutes, the fans go off. I found this the best way to cool with fans. They have a delay time to remove any residual heat. They then turn off to reduce the amount of dust and dirt that get circulated. 73, Joe, K1ike Mike Dietrich wrote: Sounds like the best thing to do is a combination of both the PTT and Thermodisk versions together. That way the fan starts blowing when users start using the repeater. Then the thermodisk takes over after it heats up until all traffic quits and the tx'er cools down. Just my 2c worth. Merry Christmas everybody!! Mike Yahoo! Groups Links
Re: [Repeater-Builder] Re: fan timer circuit
Maybe it's just me, but I've never understood the need for a special circuit to run cooling fans. I run my fans from the PTT line using a relay. I have also used a simple chassis thermostat, but prefer using PTT. I suppose you could easily use both methods so that in the event that the equipment remained too warm when PTT halts, the thermostat could keep it running longer. However, I contend that if this is happening, your fans are inadequate and not keeping up with the demand right along. Why the need to continue cooling after the QSO has ended? Just because you can? Chuck WB2EDV - Original Message - From: skipp025 skipp...@yahoo.com To: Repeater-Builder@yahoogroups.com Sent: Sunday, December 21, 2008 12:24 PM Subject: [Repeater-Builder] Re: fan timer circuit Re: fan timer circuit I've seen a number of fan delay, time on, time off circuits posted on web. The neat'o web page url I just posted here on the group has one and it might be the one you're looking for. http://www.w1ghz.org/small_proj/small_proj.htm and the fan controller information is about half way down the page with a picture and down-loadable zip file. My own personal preference is to run everything warm and even a lot higher temp than most of you would expect. In a repeater station operation only an RF PA and un-modified Astron Power Supply with an undersized heat sink might get a fan. Never a failure of a well planned installation. Some of our local start-up radio clubs throwing repeater packages in place often start out using and stay with an external RF amplifier designed for mobile operation. Sometimes the amp runs so hot you can't keep your hand on the heat sink but I've yet to see one fail. cheers, skipp
Re: [Repeater-Builder] Re: fan timer circuit
At 12/21/2008 09:24, you wrote: Some of our local start-up radio clubs throwing repeater packages in place often start out using and stay with an external RF amplifier designed for mobile operation. Sometimes the amp runs so hot you can't keep your hand on the heat sink but I've yet to see one fail. cheers, skipp 70 °C, the upper operating temperature limit of many RF devices, is too hot to touch. However, MTBF will definitely be reduced. In addition, without better cooling the devices board will experience greater temperature extremes, which would result in more failures caused by thermal cycling. Mobile amps often lack adequate power supply bypassing, resulting in a lot of in-cabinet RF coming off the amp's power leads. This can be avoided by feeding the +12V through bypass capacitors or high current EMI feedthroughs, rerouting the - power connection directly to the case instead of through an unbypassed terminal strip. Bob NO6B
Re: [Repeater-Builder] Re: fan timer circuit
I moved over to utilizing the PTT instead of the thermostat disks after I'd had a few thermostats fail. But I agree with your thinking. In my mind the slight inefficiency of running my fans earlier than the heat builds up is not significant to me. I like to think it slows the heat buildup. Once everything reaches a stable temperature and the repeater goes idle, there is no new heat generated and things cool more gradually without the fan blowing. But this is nit-picking. Either way works fine without adding unnecessary circuitry. Chuck WB2EDV - Original Message - From: wb6fly wb6...@verizon.net To: Repeater-Builder@yahoogroups.com Sent: Sunday, December 21, 2008 4:27 PM Subject: [Repeater-Builder] Re: fan timer circuit I mostly agree. My thinking is that a fan that runs continuously wastes power and draws dust and dirt into the equipment. I also believe that a fan that runs only during PTT is not doing much good except on very long transmissions- when the heat of the PA has made it to the fins. It may take several minutes of key-down time before the fins start getting warm, so running the fan before then is ineffective. My practice is to fix a normally-open thermal switch to one of the heat-sink fins, using heat-sink compound for good heat transfer. I have found that a switch that closes at 122 degrees Fahrenheit (50 degrees Celsius) works best, since it opens about ten degrees lower, and provides near-ideal hysteresis. The thermal switch directly controls a small AC or DC fan that blows on the fins. Not only is this an extremely simple solution, but it ensures that the fan will run only when needed and for as long as needed. I use a Cantherm switch that Digi-Key sells under catalog number 317- 1094-ND for about $7. 73, Eric Lemmon WB6FLY
Re: [Repeater-Builder] Re: fan timer circuit
One Summer's day in Los Angeles I had a service call on a microwave repeater (vacuum tube). It was located in a warehouse, near the roof. In the heat I lugged my stuff up the stairs. As I set down the service monitor I leaned my other arm against the cabinet. I jerked it away because it was burning my forearm. I was impressed that the equipment would operate at those temperatures; but I'm sure that the MTBF was reduced. Mike - AA8K n...@no6b.com wrote: 70 °C, the upper operating temperature limit of many RF devices, is too hot to touch. However, MTBF will definitely be reduced. In addition, without better cooling the devices board will experience greater temperature extremes, which would result in more failures caused by thermal cycling.
Re: [Repeater-Builder] Re: fan timer circuit
Sounds like the best thing to do is a combination of both the PTT and Thermodisk versions together. That way the fan starts blowing when users start using the repeater. Then the thermodisk takes over after it heats up until all traffic quits and the tx'er cools down. Just my 2c worth. Merry Christmas everybody!! Mike
Re: [Repeater-Builder] Re: fan timer circuit
At 12/21/2008 14:01, you wrote: I moved over to utilizing the PTT instead of the thermostat disks after I'd had a few thermostats fail. But I agree with your thinking. My thoughts as well: the thermostat is an elegant solution, but if it fails, your repeater fails in a rather expensive way. One reason why I've dismissed using any switching on my 110 V cooling fans let them spin 24/7. The 12 V fans get switched by PTT, though I use a separate buffer transistor to key them. Otherwise the fan motor dumps noise onto the PTT line, which finds its way into the TX audio. You could wire two thermostats in parallel so if one opens up you don't lose cooling. However, to be an effective safeguard against failure they should be independently tested when doing your PM. Bob NO6B
Re: [Repeater-Builder] Re: fan timer circuit
n...@no6b.com wrote: One reason why I've dismissed using any switching on my 110 V cooling fans let them spin 24/7. I have used 220 V muffin fans on 110 V and they last for years. I put one in service in 1997, and it's still turning. Kevin
Re: [Repeater-Builder] Re: fan timer circuit
Kevin, another method of slowing down an AC fan is to put a capacitor in series with the AC leads as a voltage dropping element. A local Ham played with this idea many years ago and as I recall he started with a 1 Mfd paper capacitor. In his case he dropped the voltage to around 90 volts to the fan. 73 John VE3AMZ - Original Message - From: Kevin Custer To: Repeater-Builder@yahoogroups.com Sent: Sunday, December 21, 2008 8:58 PM Subject: Re: [Repeater-Builder] Re: fan timer circuit n...@no6b.com wrote: One reason why I've dismissed using any switching on my 110 V cooling fans let them spin 24/7. I have used 220 V muffin fans on 110 V and they last for years. I put one in service in 1997, and it's still turning. Kevin
Re: [Repeater-Builder] Re: fan timer circuit
One more thing to be careful of when using fans on remote equipment. Make sure there are guards on both sides of the fan. We had a muffin fan on a 100wt 220 amp that failed when a mouse tried to get closer to the warm heatsink. His carcass jammed the fan blades and got dessicated with the heat. Burt Lang VE2BMQ
RE: [Repeater-Builder] Re: fan timer circuit
m... From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Burt Lang Sent: Sunday, December 21, 2008 10:39 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: fan timer circuit One more thing to be careful of when using fans on remote equipment. Make sure there are guards on both sides of the fan. We had a muffin fan on a 100wt 220 amp that failed when a mouse tried to get closer to the warm heatsink. His carcass jammed the fan blades and got dessicated with the heat. Burt Lang VE2BMQ __ NOD32 3709 (20081220) Information __ This message was checked by NOD32 antivirus system. http://www.eset.com
RE: [Repeater-Builder] Re: fan timer circuit
a mouse tried to get closer to the warm heatsink. His carcass jammed the fan blades and got dessicated with the heat. Burt Lang VE2BMQ Yes I guess that could Happen , I live in a City and My 6 Month old Fridge quit working , Well of Course bring a Ham Some of us including Me thing We can fix anything , I pulled it out from the wall and Found a Dead Mouse caught up in the Fan blade stopping it . I dug it out and cleaned it out put a screen over it, Plugged it in and it has been working great now for a couple of years. My Wife likes to use Decon , I understand the Mice swell up and look for water then go behind the walls etc and Decay and smell . So it was all Her fault Happy Holidays Don
