Samlex America PST-200S-24E - Manual (Page 10)

10 | SAMLEX AMERICA INC.
Power Rating of the inverters
The continuous output power rating of the inverter is specified in Active Power in Watts
for resistive types of loads like heating elements, incandescent lamps etc. where Power
factor (Pf) = 1. The Surge Power rating is for < 1 sec.
Non resistive / reactive loads with Power factor < 1 like motors (Pf = 0.4 to 0.8), non
Power factor corrected electronics (Pf = 0.5 to 0.6) etc, will draw higher Apparent Power
in Volt Amps (VA). This Apparent Power is the sum of Active Power in Watts plus Reac-
tive Power in VAR and is = Active Power in Watts ÷ Power factor. Thus, for such reactive
loads, higher sized inverter is required based on the Apparent Power. further, all reac-
tive types of loads require higher inrush / starting surge power that may last for
> 1 to 5 sec and subsequent lower running power. If the inverter is not sized adequately
based on the type of AC load, it is likely to shut down or fail prematurely due to
repeated overloading.
i
inFo
The manufacturers’ specification for power rating of the appliances and devices
indicates only the running power required. The surge power required by some
specific types of devices as explained above has to be determined by actual test-
ing or by checking with the manufacturer. This may not be possible in all cases
and hence, can be guessed at best, based on some general rules of thumb.
Table 2.1 below lists some common loads that require high surge power on start up. A
“Sizing factor” has been recommended against each which is a multiplication factor
to be applied to the rated running Watt rating of the load to arrive at the Continuous
Power rating of the inverter (Multiply the running Watts of the device/ appliance by the
Sizing factor to arrive at the size of the inverter).
tABLe 2.1: inVeRteR SiZinG FActoR
type of Device or Appliance
inverter
Sizing Factor*
Air Conditioner / Refrigerator / freezer (Compressor based) 5
Air Compressor 4
Sump Pump / Well Pump / Submersible Pump 3
Dishwasher / Clothes Washer 3
Microwave (where rated output power is the cooking power) 2
furnace fan 3
Industrial Motor 3
Portable Kerosene / Diesel fuel Heater 3
Circular Saw / Bench Grinder 3
Incandescent / Halogen / Quartz Lamps 3
Table Continues Next Page ►
seCtIOn 2 | General Information