posted on Mar, 4 2006 @ 06:42 AM
Originally posted by scienceguy94
The answer is no. An ac voltage is a sinewave while a DC is a flat line the line and sinewave go through potential functions with respect to time. If
your trying to make hight votlage ac you might connect your alternators together and then use a inverter and step transformer to get your high
voltage. I hope this answers your question.
with an inverter you don't really need a step up transformer. your primary winding is center tapped with a small number of turns, your secondary
winding has the number of turns needed to make the turns ratio correct for what ever voltage you want on the output. i.e. 12v in with 10 turns
would need 100 turns for 120 v out
Originally posted by apc
Plenty of ways to get usable voltage AC from DC... as you said an inverter is the easiest route, but you lose a lot of power in the form of heat.
yes and no
linear transformers don't lose much untill they are loaded down and then as you approach a short on the output, the power used by the transformer
goes way up.
in a ferroresonant transformer you lose about 100 watts energizing it at no load. if you use some of the extreamly low Rds on mosfets (about 10 each
side is a nice start) you can virtually eliminate the power loss in your switching transistors. i've gotten down to less that 10 watts dissipation
on the switching tansistors under 1kw load.
there's also a couple of advantages that a ferro has over linear transformers.
a linear can produce a sinewave output, but you have to do some fancy switching to achieve it. in a ferro instead of interlacing your e-i
laminations you bundle all the e laminations together and mill a few tenths of an inch off the center leg. then when you add your coils and top it
off with the i laminations you will get a signwave with simple switching on and off. infact a very pretty sinewave compared to what you get out of
in a linear you short the output you also reflect the short to the input and if you don't detect it quick enough your switching transistors smoke
faster than tommy chong and a joint. a ferro on the other hand, when a short is placed on the output the voltage folds back and only a fraction is
reflected back to the input and your switching circuit doesn't go poof.
a linear also has to have output sensing feedback to control the switching circuit, a ferro on the other hand,also known as a constant voltage
transformer, is self regulating so you don't really need any output sensing feedback. you just set your turns ratio to produce the desired output
voltage and then for regulation you adjust your capacitor on the tank circuit
the only down side to a ferro is the amount of power needed to energize the tank circuit