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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)
= (Power consumpition)
(Output of electrical appliance)
(Efficiency)
The smaller the motor, the
lower the efficiency.
Table. 3-1
(
)
L
E
D
O
M
1
0
1
4
V
G
R
1
0
1
6
V
G
R
y
c
n
e
u
q
e
r
F
z
H
0
6
.
c
t
e
,
r
e
t
a
e
h
,
p
m
a
l
t
n
e
s
e
d
n
a
c
n
I
W
0
0
6
3
W
0
0
8
4
,
l
o
o
t
n
e
v
i
r
d
-
r
o
t
o
M
,
p
m
a
l
t
n
e
c
s
e
r
o
u
l
F
e
s
o
p
r
o
p
-
l
a
r
e
n
e
g
.
x
o
r
p
p
a
W
0
0
8
1
.
x
o
r
p
p
a
W
0
0
4
2
.
c
t
e
,
p
m
a
l
y
r
u
c
r
e
M
.
x
o
r
p
p
a
W
0
0
4
1
.
x
o
r
p
p
a
W
0
0
6
1
.
c
t
e
,
r
o
s
s
e
r
p
m
o
c
,
p
m
u
P
.
x
o
r
p
p
a
W
0
5
8
.
x
o
r
p
p
a
W
0
0
1
1
