Paul and John,
Thanks for juggling my brain. Yes, I stand corrected. I was thinking
about the little Bird 1 kW water load, that is stricktly water
cooled, by water flowing over and inside a single cermet resistor
tube. They use that technology up into the 50 kW water loads as well,
and Altronics makes it up to 200 kW. What i replied to was referring
to those types of loads. The Bird 8230, now that I look in a Bird
catalog, is just like the 1kW oil filled boxes except having the
water tubing. Having oil immersion cooling does wonders for the load,
as it has good heat transfer,and adds dielectric breakdown strength
around the element inside.
As for the Bird 8141 250W oil filled load, I would agree that you
could run it higher for a short time, but keep an eye on the
temperature, add fans, watch the rubber bladder on the end. 1.5 kW is
a big multiplier over the CW rating of that load.
I have two Altronics 200 kW film loads hooked up through a 3 dB
hybrid power splitter at work, made from 6 1/8 line, for an upcoming
test of new 500 kW tetrode power amplifier. It will be pulsed
however, and average power is more like 70 kW. It would have been
destructive to run a single load at that peak power, with 10% DF,
according to discussions with the manufacturer. So i paralled them.
73 and happy holiday,
John
K5PRO
Hi John
Are we talking about the same type loads? My 2500 watt load uses an oil
dielectric that is cooled with a water loop immersed in the oil. It could
be a Bird 8230 but it's marked with a military number, it looks the same and
is rated the same, 200 watts without water and 2500 with circulation. I
have run this load at 6KW SSB for short periods with no apparent damage.
I've haven't tried bacon but the spiders in the cooling fins leave in a
hurry!!
73, from rainy Oregon, Paul
PAUL HEWITT
WD7S PRODUCTIONS
QRO HOMEBREW COMPONENTS
http://wd7s.home.att.net
Date: Sat, 13 Dec 2003 18:58:15 -0500
From: "John" <brazos@rochester.rr.com>
To: <amps@contesting.com>
Subject: [Amps] Re: Amps Digest, Vol 12, Issue 29
Message-ID: <006601c3c1d4$fb28f9e0$28a0ac44@aoldsl.net>
References: <20031213170026.1858E31A100@dayton.akorn.net>
Content-Type: text/plain;
charset="Windows-1252"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Precedence: list
Message: 10
Hi Cliff , I just got a bird 8141 dummy load from bird and it is rated at
250 watts continuous that should translate to well over 1.5 KW for short
periods of time . Thiswas told to me by a dealer in these surplus dummy
loads. check with Max Gain systems in marietta GA. John
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|