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Power Inverter wave forms
The Power Inverter is a good starting point for most systems when solar electric is required
for household items. Such as lighting, Computer, TV or stereos. These inverters make the
world more plug and play being most of the world uses AC current.
The Inverter is a device that changes DC (direct current) current into AC (alternating
current) current. Alternating current comes in many wave forms. The first type of AC current
was a square wave form inverter. A really crude wave form compared to today’s true sine
wave also known as pure sine wave. However in the mid point there is a modified wave which
is just a step above the square but not as good as the true sine wave. A True sine wave
inverter is used for fine or delicate instruments such as used in a hospital or lab work where
you don’t want the power floating. But has turned in to the standard inverter because it is
the closest thing to grid power and in a lot of cases better then grid power.
DC voltage does not have a wave form. It is a direct line there and a direct line back so it is
called Direct Current. The sine wave of AC voltage goes above the zero voltage mark to a
set positive voltage and then goes below the zero voltage mark to a set negative voltage. So
it is called Alternating Current because it is alternating from a positive to a negative.
Looking at the two inverter wave forms below. The power inverter wave form starts at zero
voltage going up, it then starts back down passes zero to the negative peak and then on to the
next zero voltage going up. This is called one cycle or a hertz. Normally there are 60 of these
cycles or 60 hertz per second in a sine wave. Some inverter sine wave forms might be 50
cycles or they could be 60 or greater or even float. This odd wave form and cycle count
confuses clocks, bread makers and battery chargers. It is normally found in cheap a
inverter.
The picture above is an AC inverter modified sine wave form. If you notice it has a step up,
step across, and step down form. It is like the crude square wave form because it clips the
tops and bottoms off the wave making a flat and is either strait up or down when going to the
positive or negative side ends. It just has an extra step at zero voltage. These flat spots in
the wave form is where the hammering sound comes from in electric motors and the noise
you hear in cheap radios. An electric motor or compressor will not have as long of a life
using this type of inverter wave form.
This picture is from a true sine wave power inverter. It is the type of wave form you would
see from the city electric grid. It is what that you find in your home. This is the type of
wave form you find in a True sine wave inverter. Smooth and rounded all the way.
Motors will run quiet and radios will not have the interference like with a modified sine wave
inverter. Just looking at the two wave forms you can see how much better things would run
with a true sine wave inverter.