Saturday, January 10, 2009

The Quest for Power

Over the last twelve months my astronomy has been more of a course in electronics - something that in my university days I saw as nuisance and relevant only to the propeller heads in Elec. Eng. Add to that total and complete colour blindness and I'm sure you'll agree it was probably fairly pointless putting a bunch of resistors and capacitors in front of me. I was and am, much happier at a larger component level.

In the quest for significant amateur astronomy the old telescope was disposed of for a you beaut computer controlled model - a Celestron CPC8. All sorts of back-end gear was added - a filter wheel, temperature compensated focuser, field rotator (just to complicate it). Of course everything is powered and it all can be computer controlled. So everything needs power. All the electronic components use DC power and one objective was to be portable. After a few shake-down runs success looked achievable - soon however some gremlins started to show. The heavy duty marine GEL battery still capable of powering an electric outboard on a small boat - couldn't cope with the draw of most of the gear - OUCH1

So the solution is to use a Laboratory Power Supply, at least when within range of a residential power supply. Still this meant acquiring or building a distribution box for the 12V supply. This was completed with a lot of burnt fingers, cursing and trepidation. All this was fine for 12V requirements, and of course there is the few components that require odd voltages and need a step down DC-DC transformer - simple to say , however fraught with difficulties. The most significant issue is that the excess power needs to be shed and disposed of, and this is done by converting it to heat - well this is simply the outcome. The bigger the voltage drop the more heat. The problem this creates is that the electronics to handle the DC shift are compact, the cooling heat sink fins can be large. Correspondingly the housing box goes from small to large. Anyway the bottom line is a complete redesign but I should achieve a reduction in long cables thus removing another risk factor of something that trip up the scope in the middle of a run.

So I'm still out of action and almost back to step 1 but about to make a come back.

No comments:

Post a Comment