SamplexPower SAM Serie Mode D'emploi page 6

SECTION 2 |
Load controlled cooling fan
Cooling is carried out by convection and by forced air circulation by load-controlled fan.
The fan will normally be off and will be switched oN automatically at the following
loads:
SAM-1000-12
SAM-1500-12, SAM-2000-12 & SAM-3000-12
This will reduce energy consumption by the fan and will increase overall efficiency
principle of operation
Conversion of 12 VDC from the battery / other DC source to 115 VAC takes place in 2
stages. In the first stage, the 12 VDC is converted to high voltage DC (around 160 VDC)
using high frequency switching and Pulse Width Modulation (PWM) technique. In the
2nd stage, the 160V high voltage DC is converted to 115V, 60 Hz Modified Sine Wave AC.
(Note: 115 V is the RMS value of the Modified Sine Wave AC voltage. The peak value of
the Modified Sine Wave AC voltage will be equal to the value of the above high voltage
of around 160V. See the fig 2.1 below)
modified Sine Waveform -
characteristics & comparison with pure Sine Waveform
Please refer to Fig 2.1 below which shows one cycle of Modified Sine Wave and Pure Sine
Wave for comparison.
V +
V -
4 | SAMLEX AMERICA INC.
Description, Features &
Principle of Operation
180
160
140
120
100
80
60
40
20
0
20
40
Pure Sine Wave
60
crosses 0V
80
instantaneously
100
120
140
160
180
TIME
Fig 2.1 Modified Sine Wave and Pure Sine Wave - Comparison
28 to 32 Watts
90 to 110 Watts
Modified Sine
115 RMS
Wave sits at
0V for some
time and then
rises or falls
Legend
Modified Sine Wave
Sine Wave