Hi all, i'm quite new to this game, and i've been playing a bit.. i've got a few questions that some of you may be able to answer, but first some backgroudn.
I've been tinkering with some Fisher Pakeyl Motors, and since they are cheap, readily available and mechanically easy to work with, i want to continue with them.. both for hydro and wind.
I immediately was quite suprised with what most peopel seem to do, which is rewire the stator, and convert them to low voltage.. I figured that the high voltage output was considerably better as i would get less loss in cables / slip rings etc. I also was quite taken back that most people just attached their batterys to some retified DC from the mill.. It works.. but not particually efficently..
I read in some other postings that people have tryed using PC power supplys, with Universal inputs, to produce a constant voltage output from the so called 'wild' AC that they get from their mill. That concept quite appealed.. as it used cheap and easy to get components.. Of course i realised that i would need to control the current flow into the batterys.. A simple PWM switching solution sorts that out.. I used a reflashed linksys wrt54gs running openwrt ( www.openwrt.org ) and a few one wire devices to read the frequency of the incoming ac, and set the width of a PWM chopper on the ouputs of the ATX powersupplys ( one per phase ), 5V outputs wired in series to get 15V which works quite well as a charger.
What is good about using the ATX power supplys with the Universal input is that they deal with my 'wild' AC pretty well.. ( no smoke as yet )..
Today, i went looking for some bigger power supplys, so i could perhaps run a bigger mill.. It seems that theres not really anything much larger than 300W, with a universal input.. Most of what i looked at was universal to about 100W, and then it was a manual switch to deal with two ranges.. ( 120V / 230V +/- a bit ) ...
Why is this?? Is there some problem with dealing to such a wide voltage input at higher voltages?? Alternatively does anyone know of a design or supply of a SMPS that will cope with my 'wild' AC source.. Ideally i'd like to get rid having to have three differnt p/s, so i don't mind building somethign.. ( if it is possible )
It also made me think.. Perhaps this design is not really that efficent.. Are universal input Switch mode power supplies not good for efficency.. At 3W for your cellphone charger i guess its not a problem, if you run at 50%.
I look forward to any help anyone can offer..