-
19
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(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.
Efficiencies of some electrical appliances are as follows :
Single-phase motor................................ 0.6 to 0.75
Fluorescent lamp ................................... 0.7 to 0.8
Example 1: A 40W fluorescent lamp means that its luminous output is 40W. Its efficiency is 0.7 and
accordingly, power consumption will be 40 ÷ 0.7= 57W. As explained in Item (2), multiply
this power consumption value of 57 W by 1.2 to 2 and you will get the figure of the neces-
sary capacity of a generator. In other words, a generator with a rated output of 1000W
capacity can light nine to fourteen 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 capacity of the generator should be multiple of 570 W by 1.2 to 3 as
explained in the ltem (3). 570 (W) x 1.2 to 3 = 684 (W) to 1710 (W)
Table. 7-1
The smaller the motor, the
lower the efficiency.
()
= (Power consumpition)
(Output of electrical appliance)
(Efficiency)
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W0082.xorppaW0003.xorppa
.cte,pmalyrucreMW0081.xorppaW0002.xorppa
.cte,rosserpmoc,pmuPW0031.xorppaW0041.xorppa
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