[Amps] Liquid Cooling

[Paul Christensen]

Correction to my last post -- typical leakage current of the Alpha Seventy 
is 200 uA @ 4KV.  I had to get up out of my hair and re-confirm the leakage 
scale.  It's at 1 mA where the "high leakage" sensor engages.

One sensor is used to monitor both leakage current and low-water level. 
When the leakage level is below 100 uA, the comparator circuit assumes that 
the ultra-low leakage is the result of low water volume.  When the cooling 
system is purged and new distilled H2O is added, I will see the "low level" 
indicator engage, knowing that the system level is adequate.  After about 
30-45 minutes, enough ionization occurs in about 1 pint of H2O to raise the 
leakage current up to 200 uA, and there it stays for many months of 
operating.

Paul, W9AC

----- Original Message ----- 
From: "Paul Christensen" <w9ac at arrl.net>
To: <amps at contesting.com>
Sent: Tuesday, April 06, 2010 12:15 PM
Subject: Re: [Amps] Liquid Cooling


>> have the heat exchanger grounded through a 0-1ma meter....My water
>> reservoirs contain 12 liters of distilled water....
>
> That should stay pure for a while!  The Alpha Seventy's reservoir
> (topped-off tube boiler, condenser, and feed line) is roughly 700 mL 
> (about
> 3 cups of H2O).  The bottom of the condenser forms a large portion of the
> reservoir.  Leakage is typically 1 mA @ 4KV.  At 1KW TPO brick-on-the-key,
> the assist from the whisper fan keeps the H2O temperature well under
> boiling, although I've never measured it.  That's actually a good 
> parameter
> to monitor.  I'll need to think of a way to easily measure H2O temperature
> without affecting system leakage current.   Ideas, anyone?
>
> Current leakage to
>> ground is typically 200ua at room temperature rising to around 350-400ua
>> at 40C....It takes a long CW session to warm the water past 30C with
>> this system...
>
> Bob, I sure would love to see some photos of that cooling system.
>
> Paul, W9AC
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>