Installation Manual

© 2015 Sensata Technologies
Page 57
Appendix C – Power Consumption and Output Waveforms
• Square Wave – The simplest AC waveform. Some types of equipment behave strangely
when powered from a square wave inverter.
• Modifi ed Sine Wave – Also referred to as a “quasi sine wave”. This output looks like a one-
step staircase and the waveform changes its width to continually provide the correct RMS
output voltage regardless of the battery voltage. Most loads that run from a sine wave will
also run from a modifi ed sine wave. However, things such as clocks and furnace controllers
may have trouble.
• Pure Sine Wave – An AC waveform that looks like rolling waves on water. It rises and falls
smoothly with time. The grid puts out a sine waveform. Any plug-in AC equipment will operate
from a sine wave inverter.
Figure C-1, AC Waveforms
TIME
VOLTAGE
40
80
0
120
40
160
200
80
120
160
200
Modified
Sine Wave
Pure Sine
Wave
Square Wave
C-2 Inverter Output Waveforms
The inverter’s output waveform is the shape of the wave that alternating current makes as its
voltage rises and falls with time. Today’s inverters come in three basic output waveforms: square
wave, modifi ed sine wave, and pure sine wave (see Figure C-1).