[Amps] WATER for vapor cooled amplifier TSPA

[Paul Christensen]

> Need to check the conductivity sometime.  What is good and bad 
> conductivity, and can I use an ohmmeter or do I need something special?

John Lyles probably knows the numbers.  In terms of the Alpha 70V, water 
leakage is measured between 0-5 mA DC, with 5 mA being off scale.  Assuming 
that the metering is correct (big assumption), I typically see well under 1 
mA of leakage even prior to the time I conduct my annual purge.

Alpha uses an interesting circuit to measure leakage and level.  In fact 
just one circuit used as a multi-state comparator.  The only problem with 
this approach is that immediately after adding clean water, the LEVEL 
indicator may illuminate if there is extremely little leakage.

The circuit is looking at the complete absence of leakage as an indicator of 
"ain't 'nough water in the reservoir." So, that threshold is fixed at very 
little current -- probably 0.05 mA or less, again assuming that the panel 
metering is close.  Moving the logic state up above this threshold of 0.05 
mA and to about 2 mA establishes the so-called "normal" zone and neither 
lamp is lighted.  But get above 2 mA and the LEAKAGE lamp illuminates. 
Despite the use of such a simple circuit, I have never encountered a level 
lamp issue absent the first ten minutes of amp operation when the water is 
perfectly clean.

Paul, W9AC