3.2. The Output Waveform
The AC output waveform of the inverter is known as “modified sine wave”. It is a waveform
that has characteristics similar to the sine wave shape of utility power. This type of waveform
is suitable for most AC loads, but may not be suitable for scientific equipment. Always
consult the manufacturers manual where necessary.
Figure 2
Modified sine wave and sine wave comparison
The output from this inverter has an RMS (root mean square) voltage, the same as that
found in a normal standard household - 230V. It should be noted, that most AC voltmeters
(both digital and analog) are sensitive to the AVERAGE value of the waveform rather
than the RMS value, and are calibrated for RMS voltage under the assumption that the
waveform measured will be a pure sine wave. These meters, therefore, will not read the
RMS voltage of a modified sine wave correctly, and will read about 20 to 30 volts lower
than the true voltage, when measuring the output of the inverter.
4. INSTALLATION
4.1. Power Source Requirements
The power source must provide between 11 and 15 volts DC and must be able to supply
the necessary current to operate the load. The power source may be a battery or a well
regulated DC power supply. To obtain a rough estimate of the current (in amperes) the
power source must deliver, simply divide the power consumption of the load (in watts
AC) by 10.
Example: if a load is rated at 300 watts AC, the power source must be able to deliver: 300
divided by 10 = 30 amperes
CAUTION: the inverter must, be connected only to batteries with a nominal output voltage
of 12 volts. The unit will not operate from a 6-volt battery and will sustain permanent damage
if connected to a 24-volt battery.
4.2. Connection to Power Source
The inverter is provided with a fused cigarette lighter plug and battery cables with clamps
for connection to a suitable battery:
CAUTION:
Do not use with positive earth electrical systems (The majority of modern
vehicles, , and lorries are negative earth).
-5-
Sine Wave
Modified Sine Wave
