Statpower Portawattz 3000, Owner'S Manual, Page: 6 / 36

2
2.2 Portawattz
TM
3000 Inverter Output Waveform
The AC output waveform of the Portawattz 3000 is called a “quasi-
sine wave” or a “modified sine wave”(see Figure 2). It is a stepped
waveform that is designed to have characteristics similar to the sine
wave shape of utility power. A waveform of this type is suitable for
most AC loads, including linear and switching power supplies used
in electronic equipment, transformers, and motors. This waveform
is much superior to the square wave produced by many other DC to
AC inverters.
The modified sine wave produced by the Portawattz 3000 is designed
to have an RMS voltage of 115 volts, the same as standard household
power. Most AC voltmeters (both digital and analog), are sensitive
to the average value of the waveform rather than the RMS value.
They are calibrated for RMS voltage under the assumption that the
Figure 1 - Principle of Operation
Figure 2. Modified Sine Wave