SamplexPower PST-1500-12 Mode D'emploi page 9

SECTION 2 |
Resistive Load: A device or appliance that consists of pure resistance (like filament
lamps, cook tops, toaster, coffee maker etc.) and draws only Active Power (Watts) from
the inverter. The inverter can be sized based on the Active Power rating (Watts) of
resistive type of loads without creating overload (except for resistive type of loads with
Tungsten based heating element like in Incandescent Light Bulbs, Quartz Halogen Lights
and Quartz Halogen Infrared Heaters. These require higher starting surge power due to
lower resistance value when the heating element is cold).
Reactive Load: A device or appliance that consists of a combination of resistive, inductive
and capacitive elements (like motor driven tools, refrigeration compressors, microwaves,
computers, audio/ video etc.). The Power Factor of this type of load is <1 e.g. AC motors
(PF=0.4 to 0.8), Transformers (PF=0.8), AC to DC Switch Mode Power Supplies (PF=0.5
to 0.6) etc. These devices require Apparent Power (VA) from the AC power source. The
Apparent Power is a vectorial sum of Active Power (Watts) and Reactive Power (VAR).
The AC power source has to be sized based on the higher Apparent Power (VA) and also
based on the Starting Surge Power.
2.2 OUTPUT VOLTAGE WAVEFORMS
180
160
140
120
100
80
60
40
20
0
20
Pure Sine Wave
40
crosses Zero Volt
60
instantaneously
80
100
120
140
160
180
TIME
Fig. 2.1: Pure and Modified Sine Waveforms for 120 VAC, 60 Hz
The output waveform of the Samlex PST series inverters is a Pure Sine Wave like the
waveform of Utility / Grid Power. Please see Sine Wave represented in the Fig. 2.1 that
also shows Modified Sine Waveform for comparison.
In a Sine Wave, the voltage rises and falls smoothly with a smoothly changing phase
angle and also changes its polarity instantly when it crosses 0 Volts. In a Modified Sine
Wave, the voltage rises and falls abruptly, the phase angle also changes abruptly and
it sits at zero V for some time before changing its polarity. Thus, any device that uses a
General Information
V = 169.68V
PEAK
V = 140 to 160V
PEAK
V = 120 VAC
RMS
Modi ed Sine
Wave sits at
ZERO for some
time and then
rises or falls
16.66 ms
Sine Wave
Modi ed Sine Wave
SAMLEX AMERICA INC. | 9