SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE
7
Efficiencies of some electrical appliances are as
follows:
Single-phase motor 0.6 to 0.75
Fluorescent lamp 0.7 to 0.8
(The smaller the motor, the lower the efficiency)
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 necessary 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) × 1.2 to 3 = 684
(W) to 1710 (W).
x R x I x L
Voltage drop indicates as V =
NOTES:
Wiring between generator and electrical
appliances
1.
Allowable current of cable
Use a cable with an allowable current that is higher than
the rated input current of the load (electrical appliance).
If the input current is higher than the allowable current
of the cable used, the cable will become excessively
heated and deteriorate the insulation, possibly burning
it out. Table below shows cables and their allowable
currents for your reference.
2.
Cable length
If a long cable is used, a voltage drop occurs due to the
increased resistance in the conductors decreasing the
input voltage to the load (electrical product). As a result,
the load can be damaged. Table below shows voltage
drops per 100 meters of cable.
R =
resistance ( / 100 m) on the above table
I =
electric current through the wire (A).
l =
the length of the wire (m).
The lenght of wire indicates round length, it means twice
the length from generator to electrical tools.
1
100
W
MEASURING PROCEdURES
MEASURING INSTRUMENTS
VOlTMETER
AC voltmeter is necessary.
The approximate AC voltage
ranges of the voltmeters to
be used for various types of
generators are as follows:
0 to 150 V :
Type with an output
voltage of 110 or 120 V
0 to 300 V :
Type with an output
voltage of 220, 230 or 240 V
0 to 150 V, 0 to 330 V : Dual
voltage type
1
4
2
3
AMMETER
AC ammeter is necessary.
An AC ammeter with a range
that can be changed according
to the current rating of a given
generator is the most desirable.
(About 10 A, 20 A, 100 A)
CIRCUIT TESTER
Used for measuring resistance,
etc.
FREQUENCY METER
Frequency range : About 45 to
65Hz
NOTE :
Be careful of the
frequency meter’s input voltage
range.
5
MEGGER TESTER
Used for measuring generator
insulation resistance.
Select one with testing voltage
range of 500V.
