Amps
[Top] [All Lists]

Re: [Amps] GU-84B Cooling

To: amps@contesting.com
Subject: Re: [Amps] GU-84B Cooling
From: pa3duv@planet.nl
Reply-to: pa3duv@planet.nl
Date: Wed, 20 Jul 2005 13:47:04 +0200
List-post: <mailto:amps@contesting.com>
Van   pa3duv@planet.nl  
Verstuurd op  woensdag, juli 20, 2005 11:49 am 
Aan  Will Matney <craxd@engineer.com>  
Cc    
Bcc    
Onderwerp  Re: [Amps] GU-84B Cooling 
Will,

Perhaps I could measure the anode cooler temperature with a UV 
thermometer.
"Contesting conditions" is a rather vague performance indicator, I 
could run the amplifier flat out full carrier for a defined period of 
time and then measure the cooler temperature afterwards.
I will set up a measurement session, measuring the pressure in the sub 
chassis in mm-H2O and the temperature in degrees Celcius. It is very 
difficult to measure the actual airflow without proper anemometers and 
a measurement-tube. 

The B+ current is approx. 3.5 amps @ 6000 watt output. The power gain 
is approx 20 dB and the output power is adequate. The 3-phase B+ 
transformer is switched in a delta configuration, AC voltage between 
the phases is approx 390 VAC @ 50 Hz. The airflow noise is of no 
concern to me since I always use a headset. I'll get back with some 
more detailed measurements later on.

Cheers, Dick Knol
PA3DUV



----- Oorspronkelijk bericht -----
Van: Will Matney <craxd@engineer.com>
Datum: woensdag, juli 20, 2005 10:12 am
Onderwerp: Re: [Amps] GU-84B Cooling

> Dick,
> 
> I'm not saying it's a bad tube, and dont want none to think that. 
> I just dont want anyone to undercool the tube so it will last. Who 
> knows, the 4CX1500 may have an over-sized radiator too! About the 
> only way to tell about the temp would be to use a thermocouple 
> connected to the anode. Then the temp read under contesting 
> conditions both under SSB and AM using the air flow they 
> recommend. AM/CW creates a good bit more load on one as does SSB 
> transmissions. Then if the temp stays down where it should, one 
> would know it would be ok. I'm like Rich, and what George 
> mentioned, use the largest blower possible. Another thing too is 
> maybe mount and external blower and duct it to the amp. You can 
> set one of these in another room to help kill the sound down if 
> it's a concern. On yours, you may have the right combination by 
> using enough fans both pushing and pulling. Have you measured what 
> the air flow and pressure is on your amp? If so, let us know so we 
> all have a starting point.
> 
> Best,
> 
> Will
> 
> ----- Original Message -----
> From: PA3DUV <pa3duv@planet.nl>
> To: "Will Matney" <craxd@engineer.com>
> Subject: Re: [Amps] GU-84B Cooling
> Date: Tue, 19 Jul 2005 22:45:03 +0200
> 
> > 
> > Will,
> > In my twin tube GU84B amp one fan is used to pressurize the 
> > subchassis and two axial fans to draw the air out.
> > With a B+ of 2900 VDC, from the 3 phase PSU the two GU84B tubes 
> > generate an easy 6 kW of output. During normal (6 dB compressed) 
> > SSB transmissions the exaust air stays below 55 degrees celcius.
> > Cheers, Dick Knol
> > PA3DUV
> > 
> > 
> > 
> > ----- Original Message ----- From: "Will Matney" 
> <craxd@engineer.com>> To: <amps@contesting.com>
> > Sent: Tuesday, July 19, 2005 9:53 PM
> > Subject: [Amps] GU-84B Cooling
> > 
> > 
> > > On a webpage somewhere, I cant remember now where, I read 
> about 
> > > the GU-84B (4CX1600) having an undersized radiator. I think it 
> > > was on a Russian amateur website. What I had read was this 
> tube 
> > > was actually designed for running in a missle by the Russians, 
> > > and was designed for a 1 time use. So, they undersized the 
> > > radiator a good bit because of space limitations. They were 
> > > making the comparison to a 4CX1500's radiator size being 
> larger 
> > > in the discussion. However the guts of the GU-84B supposed to 
> be 
> > > really good. So this brings the delima of how to cool it so 
> one 
> > > would get a long life out of it. One way would be add some 
> sort 
> > > of extra aluminum heat fins, or some made of brass, with fins 
> > > sticking out to catch more air, thus increasing the overall 
> > > surface area. The only other way would be to increase the 
> amount 
> > > of air flow and volume over the fins that's there. When doing 
> > > this though, the noise goes up from the blower. However, if 
> one 
> > > is going to dealve into using the GU-84B, I'd s
> > > uggest looking into this and compare the sizes between its 
> > > radiator and the one for the 4CX1500. Even though the tube is 
> > > cheaper than some others, it's still expensive if you have to 
> > > re-tube all the time. If I can remember where I seen this, 
> I'll 
> > > post the link.
> > >
> > > Best,
> > >
> > > Will
> > >
> > > -- ___________________________________________________________
> > > Sign-up for Ads Free at Mail.com
> > > http://promo.mail.com/adsfreejump.htm
> > >
> > > _______________________________________________
> > > Amps mailing list
> > > Amps@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/amps
> 
> 
> -- 
> ___________________________________________________________
> Sign-up for Ads Free at Mail.com
> http://promo.mail.com/adsfreejump.htm
> 
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
> 

 
 

_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

<Prev in Thread] Current Thread [Next in Thread>