5
FIGURE 1
Principle of Operation
2.2 THE POWER-ON-BOARD™ 400 OUTPUT WAVEFORM
The AC output waveform of the Power-On-Board™ 400 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, including linear and switching power supplies used
in electronic equipment, transformers, and motors.
The modified sine wave produced by the Power-On-Board™ 400
inverter has an RMS (root mean square) voltage of 110 volts, which is
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 waveform measured will be a pure sine wave.
These meters will not read the RMS voltage of a modified sine wave
correctly. They will read about 20 to 30 volts low when measuring the
output of the inverter. For accurate measurement of the output voltage of
this unit, use a true RMS reading voltmeter such as a Fluke 87, Fluke
8060A, Fluke 77/99 series, Beckman 4410, or Triplett 4200.
FIGURE 2
:
Modified Sine Wave
and Sine Wave Comparison
SINE WAVE
110 VAC
MODIFIED
SINE WAVE
110 VAC
