40 | SAMLEX AMERICA INC.
10. PROTECTIONS
The inverter has been provided with protections detailed below:
10.1 POWER SURGE / OVERLOAD / SHORT CIRCUIT SHUT DOWN
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INFO
Please refer to definitions of Active Power (Watts), Apparent Power (VA) and
Power Factor (PF) at Section 2.1. In the explanation below, the values of Power
are expressed in Apparent Power in VA. Corresponding Active Power (Watts, W)
will depend upon the type of load (Resistive or Reactive) and its Power Factor
(Power Factor may range from 1 to 0.5). Please note the following:
• Active Power (Watts) = Apparent Power (VA) x Power Factor (PF).
• For resistive type of loads, the Power Factor = 1 and hence, Apparent Power
(VA) = Active Power (Watts, W)
• For reactive types of loads, the Power Factor will be < 1 (up to 0.5) and hence,
the Active Power (Watts, W) will be less than the Apparent Power (VA)
The AC output voltage will shut down due to overload and short circuit conditions as follows:
Power Surge Condition: The surge rating is 1000W or 4.35A (1000W÷ 230VAC= 4.35A).
When the instantaneous value of the AC output current tries to exceed the above value
of 4.35A, output current limiting is initiated that clamps the peak instantaneous value of
output current at 4.35A. Output current limiting results in drop in the peak portion of the
AC output voltage waveform and hence, the RMS voltage also drops. The extent of volt-
age drop is proportional to the rated surge current of the load minus 4.35A. Hence, higher
surge current of the load will produce higher voltage drop. For example, considering
Resistive Load with Power Factor =1 (voltage and current are in phase), current limiting
will occur near the peak portion of the voltage waveform during every half cycle (half
cycle lasts for 10msec at 50Hz). 1000W is the value of surge power averaged over 1 to 2
msec during every half cycle of 10msec. If this situation continues for 2 to 2.5 sec, overload
condition is activated and the AC output is shut down
Overload Condition: If there is a continuous overload of 110% to 115% (660 to 690W) for
2 to 3 sec, the output voltage will be shut down. Red LED marked “OVERLOAD” (3, Fig
6.1) will turn ON and buzzer alarm will sound. The Green LED marked “POWER” (2, Fig
6.1) will continue to be lighted. The unit will be latched in this shut down condition and
will require manual reset. To reset, switch OFF the unit using the ON/OFF Switch (1, Fig
6.1), wait for 3 minutes and then switch ON the unit again. Before switching ON, deter-
mine and remove the cause of overloading.
Short Circuit Condition: Short circuit condition will be detected when the AC output
voltage drops to 160 VAC or lower over a period of around 1 to 1.5 sec. The AC output
voltage will be shut down thereafter.
SECTION 10 |
Protections
Summary of Contents for PST-60S-48E
Page 47: ...SAMLEX AMERICA INC 47 NOTES...
