🚀 go-pugleaf

In article <0001HW.BA977EAD001869E90E6B7920@news.covad.net>,
 DaveC <anon@bugus.net> wrote:

>I've been asked to help light a small office building hallway. The 
>fluorescent lamps are way too harsh for the office workers, and the tenants 
>favor the overhead QH approach. 
>
>I've looked at the local home centers' lighting departments and see quite a 
>selection of LV systems using overhead steel cable with 3 hanging reflector 
>bulbs (with a choice of trim, or not) tapped in at appropriate intervals. 
>
>Price for the above from $70-100us. 
>
>Being encouraged by what I saw, I decided to see what I could build from 
>scratch. 
>
>As you probably can guess, I'm running into current supply/demand 
>limitations. Each of the 2 hallways could use about 15 lamps. Lamps are 
>available in 20 and 50w versions, which at 12v, draw approximately 1.7a and 
>4.2a, respectively. I now see why the cost of such a system is mostly for the 
>supply. 
>
>Looking for a ready-made 12v supply, I find this at Jameco for $70us that 
>provides 12.5a:
>
><http://www.jameco.com/cgi-
>bin/ncommerce3/ExecMacro/Jameco/searchResult.d2w/report?sort=BPA&search=123422
>>
>
>This would allow me to run 7 of the 20w lamps, or only 2 of the 50w lamps. 
>
>I can't see buying 2 supplies to run the 15 (well, I guess we could rev that 
>to 14) lamps in each hall. I seem to be butting up against Ohm's Law. 
>
>Maybe build a simple, unreg'd, analog power supply with massive transformer 
>and rectifiers for 30A? 
>
>Any other ideas (or links to sites) to help me reach a solution would be 
>greatly appreciated. 
>
>Thanks,

Look for a big 12VAC transformer at an electronics surplus store.  A car 
battery charger transformer may work too.  Don't bother rectifying.  AC 
is actually a little better because it won't induce corrosion if some 
power leaks through the ceiling mounts.

As for the fluorescent lamps, make sure you have good ballasts.  The 
industrial grade (US, at least) don't have any flicker while the 
residential grade can drive you nuts.