bfesser
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45 V & 300 V Batteries for 'Geochrone'
I just received an antique seismic instrument called a 'Geochrone', made by <a href="http://en.wikipedia.org/wiki/Thiokol"
target="_blank">Thiokol Chemical Corp.</a> <img src="../scipics/_wiki.png" />, which I purchased on eBay. It's basically two <a
href="http://en.wikipedia.org/wiki/Geophone" target="_blank">geophones</a> <img src="../scipics/_wiki.png" /> with an interval timer.
I think I can get it to work again, provided the <a href="http://www.electricstuff.co.uk/dekatron.html" target="_blank">dekatron</a>
<img src="../scipics/_ext.png" />-type counter tubes are okay. My main setback is that it requires two ridiculous old <a
href="http://en.wikipedia.org/wiki/Battery_(vacuum_tube)" target="_blank">batteries</a> <img src="../scipics/_wiki.png" />—45
V (Eveready 738) & 300 V (Eveready 493).
Being a chemistry geek, should I build the cells and batteries from scratch (and, if so, does anyone have any experience building batteries similar to
those commercially produced)? Or, should I just connect a bunch of commercial batteries together in series to achieve the required voltages? Yes, I
could build an AC adapter, but the Geochrone is a <a href="http://en.wikipedia.org/wiki/Field_research" target="_blank">field</a> <img
src="../scipics/_wiki.png" /> instrument.
Not my image (mine's in slightly better condition):
<img src="../scipics/user:bfesser/geochrone.jpg" width="625" />
On a side note, when I had the instrument apart, I didn't see any O-rings which could fail catastrophically, killing me.
[Edited on 7/9/13 by bfesser]
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IrC
International Hazard
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The smart way to go is build yourself a small inverter so you can use cheap AA cells. I used to buy the one in the pic to replace both 67.5 and the
22.5 volt batteries in Geiger counters or Scintillation counters I worked on. Later I drew it and built my own. You can pick the right
transformer/windings combination to replace both batteries with a single inverter. Using two windings, two bridge circuits, you can create both your
300 and 45 volt batteries. Also the AA's last longer than B batteries loaded by pencil tube circuitry, and are available everywhere for cheap. Or use
some other size batteries depending upon the room inside the unit. CCFL ferrite transformers can be hacked from surplus stuff or you can buy a cheap
box camera to rob the flash inverter. Redesign for your needs.
Beats the hell out of finding rare, obsolete, incredibly expensive batteries. Especially since sooner or later you will need them again.
Second pic would not post unless I squished it. Instead I just rotated it. Download and rotate back. Grounding the yellow wire turned it on. You could
also hard ground the Emitters and just switch the batteries, depending upon the OEM circuitry in the unit you are powering.
[Edited on 10-24-2012 by IrC]
"Science is the belief in the ignorance of the experts" Richard Feynman
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