[Amps] Bird water load ratings

[PAUL HEWITT]

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


> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]On
> Behalf Of John T. M. Lyles
> Sent: Saturday, December 13, 2003 8:28 AM
> To: amps at contesting.com; WA4MWM at triad.rr.com
> Subject: [Amps] Bird water load ratings
>
>
> I have attempted to run 1 kW Bird water loads at higher peaks, in a
> pulsed amplifier for work.  Talking to the Bird people convinced me
> that it was not a good idea, that thin film on ceramic resistors that
> they (and Altronics in Arkansas) use cannot take much peak voltage.
> However, I believe that you are talking more about just overdrive,
> for short periods. I would not recommend it with these loads if they
> have any value to you (if you paid much for them). You could run with
> a higher Delta Temperature in your water lines, but then you start
> running the risk of boiling on the surface of the resistor. If there
> is imperfect laminar flow inside the element, with some voids that
> may not be transferring heat to the water, you risk localize hot
> spots and boiling.
>
> Better to find a bigger load, or make one. BTW, what are you doing,
> cooking some big bacon there?
>
> 73
> John
> K5PRO
>
>
>
>
> >I am in need of some info regarding the Bird 8230 dummy load.
> >
> >It is rated at 2.5kW continuous duty (with water flowing).  Is
> it rated for
> >any intermittent-duty ratings?  (i.e.  For operation at power
> levels above
> >2.5 kW at less than continuous-duty?)  If so, any reference to the
> >intermittent-duty ratings would be most-appreciated.
> >
> >Thanks for the information,
> >
> >Cliff
> >NC4CB
> >Winston-Salem, NC
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