HobbyPCB.com

Built by Hobbyist for Hobbyist!
It is currently Wed Aug 21, 2019 11:01 am

All times are UTC - 5 hours




Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: Amp temperature question
PostPosted: Wed Jun 11, 2014 8:56 pm 
Offline

Joined: Sat Feb 08, 2014 11:40 am
Posts: 7
Greetings all,
Amp 1218 is on the air and having a blast with it. I initially just used it on my Thursday night CW net as a shakedown. Since I listen more than transmit, the temp stays around the low 90's F. I used it for a couple of QSO's for the first time the other night and it was running anywhere from 100 - 110 F. I was running about 45 watts.
I was wondering if anyone was using a cooling fan and it so how did you attach it? Any other temperature comments would be welcome as well.
73,
Bob AD7BP


Top
 Profile  
 
PostPosted: Thu Jun 12, 2014 7:49 am 
Offline

Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Hi Bob,

This doesn't actually question since I've never fitted a fan on a HR50 so maybe soemone else can give you insight. But I have done the thermal analysis and the amp is perfectly safe running at heatsink temperatures up to 160F. So if you are at 110-120F a fan is not really needed unless you prefer to lower temperatures.

Since the case is slightly larger 100mm wide you might try just sitting a 100mm fan on the top of the heatsink to move the air through the fins a little better. Since the case comes from a German manufacturer I but the holes in the extrusions line up with the mounting holes in a 100mm fan so if you got some long 3mm screws you could mount a fan on the case blowing across the heatsink.

It won't take too much airflow to cool the amp down so try either running a 24V fan on the 13.8V supply or get a 220VAC fan and run it on 110V. It'll be virtually silent while still making enough airflow to do the job.

73,
Jim WA2EUJ


Top
 Profile  
 
PostPosted: Thu Jun 12, 2014 5:24 pm 
Offline

Joined: Sun Feb 09, 2014 10:57 pm
Posts: 29
Location: Redmond, WA USA
should we worry/avoid anything in particular to not add unnecessary electrical noise? The fan will be operating near the MOSFETs (albeit behind a big piece of metal)
I'm thinking about trying a PC fan with either manual (pot) or automatic speed control based on temperature.

I also understand that the temp is perfectly fine, but I like to keep my "stuff" cold enough to touch.

Thx
Thierry KF7MXQ


Top
 Profile  
 
PostPosted: Fri Jun 13, 2014 12:16 am 
Offline

Joined: Sat Feb 08, 2014 11:40 am
Posts: 7
Thanks for the reply Jim,
I had not thought of running a fan at half speed, I do notice the amp tends to shed heat pretty quickly, even without a fan. Like Thierry though, I too like to keep my gear running on the cool side also. I think I will try a 24 V DC fan and see how that works. We use DC fans on gear at work to keep the noise (electrical) to a minimum. I do understand you have designed the amp to be newbie proof, but tinkering is in my blood.
Thanks again!
73,
Bob


Top
 Profile  
 
PostPosted: Fri Jun 13, 2014 7:53 am 
Offline

Joined: Mon Jul 23, 2012 6:25 am
Posts: 1143
Hi Bob,

I did some looking around and as far as I can tell there are no 100mm fans. They seem to come in 80mm or 120mm. As for electrical noise form the fan, I'd be more concerned with coupling into the cables that go into and out of the amp than electrical coupling through the aluminum case. If you are concerned, keep the fan towards the front of the amp, the RX signal only goes through the very rear portion of the case. That keeps the fan away from the I/O cables but closer to your fingers!

73,
Jim WA2EUJ


Top
 Profile  
 
PostPosted: Fri Aug 01, 2014 8:47 am 
Offline

Joined: Fri Feb 07, 2014 7:54 am
Posts: 8
Location: Denver, CO
FYI...I ran across this fan: Nanoxia Deep Silence 92mm Ultra-Quiet PC Fan, 1400 RPM, which will run at 7 Volts with 21.5CFM at 7.2 dB(A). It's a 12V fan that comes with a 7V "adapter".

http://www.quietpc.com/na-ds-92

This fan is available on eBay.

Jay, N0MEU

_________________
73,
Jay, N0MEU


Top
 Profile  
 
PostPosted: Sun Jul 24, 2016 8:52 pm 
Offline

Joined: Sun Jul 17, 2016 3:54 pm
Posts: 7
I purchased a small 12V DC fan from my local surplus store for $4 and just laid it on top of the heat sink. I run Olivia at 30 to 40 watts for long xmissions. The little fan dropped the temperature by about 20C from 70C to 50C. I have not noted any problems with electrical noise.

The fan is from Delta Electronics, part number EFB0412HA. It is available at Mouser for $10 in singles.

73, Jim AJ8S

Attachment:
fan info.jpg
fan info.jpg [ 130.47 KiB | Viewed 3986 times ]


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group