[SECC] Amp/Temp

[halken]

Hi Cort...155 is about 68 C.  You shoiud be good with an exhaust temp of 80 C.  Your fans are a great idea...just watch that the box does not restrict the air flow.i.e. dont have it there with its fans off.73Hal N4GG


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-------- Original message --------From: Courtney Judd <k4wi at k4wi.net> Date: 10/7/17  10:58 AM  (GMT-05:00) To: RTTY Reflector <rtty at contesting.com> Cc: ACG <contest at alabamacontestgroup.org>, SECC <secc at contesting.com> Subject: [SECC] Amp/Temp 

I am looking for any ideas or your thoughts on what would be
 the safe or maximum operating temperature of a HF amplifier in rtty 
operation. My setup here is a FT5000 driving an Alpha 86 to about 1200 
watts on rtty.... it will do considerably more on cw/ssb and rtty but I 
felt that I should limit it on rtty. What started all this is that after
 about 20 years of just sitting up on the shelf doing it's thing, I 
decided to take the 86 apart and give it's internals a good cleaning. 
Sure enough, the dust bunnies had been doing their thing. Gave it a good
 cleaning but when i went to put it back together i noticed that on the 
back panel where the air enters the amp there was a pre-made place to 
install a fan. I put a 115 v fan to push air into the amp which goes 
past the transformer then into the fan below the tubes and then out the 
top thru the tube shields. On top over the vent holes I built a 
Styrofoam box with two fans to help pull the air out. Sorta a 
push-me-pull setup. I bought a couple of digital thermometers with 
sensors. I placed the probe in the airstream coming out of the amp over 
the fans in the Styrofoam box and the other the air coming out of the 
5000. This is where it got interesting. On rtty when running the 5000 
would get up to about 103 deg F. from a resting temp of 79 deg. The amp 
would go from 90 deg up to a high of 155 deg which sorta made me 
nervous. I asked my wife if eggs would fry at 155 and she said probably!
 SO, do you guys monitor your amp's temperature and what do you all 
think is save? Sorry to be so long winded but I am curious! thanks and 
73's Cort K4WI

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