5. Appliances
without any indication as to power
consumption
Some appliances have no indication as to power consumption; but instead the work load (output) is indicated. In such a
case, power consumption is to be worked out according to the numerical formula mentioned below.
(Output of electrical appliance)
(Efficiency) = (power consumption)
Efficiencies of some electrical appliances are as follows:
Single-phase motor . . . . . . . . . . 0.6 - 0.75
Three-phase motor . . . . . . . . . . 0.65 - 0.9
Fluorescent lamp . . . . . . . . . . . 0.7 - 0.8
The smaller the capacity, the worse the efficiency,
and vice versa.
Example 1: A 40 W fluorescent lamp means that its luminous output is 40 W. Its efficiency is 0.7 and accordingly,
power consumption will be 40 i
0.7
= 57 W. As explained in Item 2, multiply this power consumption
value of 57 W by 1.2 - 2 and you will get the figure of the necessary capacity of a generator. In other
words, a generator with a rated output of 1000 W capacity can light 9 - 14 40 W fluorescent lamps.
Example 2: Generally speaking, a 400 W motor means that its work load is 400 W. Efficiency of this motor is 0.7 and
power consumption will be 400 + 0.7 = 570 W. When this motor is used for a motor-driven tool, the capa-
city of the generator should be multipled by 1.2 to 3 and 570 W as explained in the item 3. Moreover,
in case when used this motor for the pump in the water or cornpresser, it is necessary 3 - 5 rimes powerful
generator according to the item 4.
Model I RGX305 I RGX405 RGX505
RGX305D RGX405D RGX505D
Frequency : 5OHz 60Ht 5OHZ 6OHZ ’ 5OHz 60Hz
incandescent lamp,
hot plate, etc. 1 2500w 2900w 3300w 3700w j 4400W 4800W
Fluorescent lamp, about about ) about
about
! about
mercury lamp, etc. 16OOW ) about
! 19OOw 2200w / 2500W 2900W I 3200W I
Motor-driven tool, ’
general-purpose about about I about i about I about
motor, etc. ! 15oow 17OOw I 2ooow , 2200w j 2%% I I
2800w
Water pump,
compressor 1 about 1 about
! i about
750W j 850W ( 1OOOW about I
I
about about
I 11oow ( 125ow 1 1400w
Table 7- 1
- 30 -