Is it possible to modify the AL-1200 blower such that the blower winding is
in series with the HV transformer primary winding as Alpha does with their
older amps? In effect, as the R.F. output power and duty cycle of the amp
increases, so does primary AC current and thus the blower's velocity
increases. For low duty-cycle operation (SSB w/o voice processor), the
blower runs at a lower speed. As the duty cycle increases with modes like
CW, and especially RTTY, the blower delivers more air "on demand."
-Paul, W9AC
----- Original Message -----
From: "Vic Rosenthal" <rakefet@rakefet.com>
To: "Amps reflector" <amps@contesting.com>
Sent: Wednesday, December 06, 2000 14:01 PM
Subject: Re: [AMPS] AL-1200 Blower
>
> "Brakob, Hans" wrote:
> >
> > The exhaust is vented just like most other amps, via
> > grille-work directly above the tube chimney. The
> > cooling seems perfectly adequate (I run mostly CW),
> > but would be nice to be able to quiet that fan down
> > a little. Since the fan is variable speed (albeit
> > "variable by moving a wire to one of four taps")
> > maybe someone has figured out an automatic switching
> > system based on internal temperature?
>
> With a solid-state amp, it's easy to mount a thermostat on the heatsink.
With
> tubes, it's more complicated...how about a thermostat clamped to the tube
anode
> cooler? Isolation from the HV would be interesting. You'd also have to
make
> sure that everything else that needs cooling (seals, tank coil, etc.)
would be
> taken care of.
>
> 73,
> Vic, K2VCO
> Fresno CA
>
> --
> FAQ on WWW: http://www.contesting.com/FAQ/amps
> Submissions: amps@contesting.com
> Administrative requests: amps-REQUEST@contesting.com
> Problems: owner-amps@contesting.com
>
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|