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Essential
alternator power ratings for selecting appropriate alternator are
given in the "PRODUCTS" links. The given power ratings
are for 1000 meters altitude, 40°C ambient temperature and Cos
phi=0,80. If the altitude is above 1000 meters, the ambient
temperature is over 40°C and the Cos phi is less than 0,80 the
alternator power can be calculated by finding the power improving
coefficients given in Table2 and 3. If the necessary is provided
concerning your load and environmental conditions, we may select
the appropriate alternator type.
EXAMPLE:
Power
required: 50 KVA
Load
and environmental conditions: Altitude 2000 m, temperature 50°C,
Power factor of load: Cos phi=0,70
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TABLE
2 Power reduction with
heigh temp.
|
| P/Pn |
Ambient
temperature |
| Elevation |
40°C
|
45°C
|
50°C
|
55°C
|
| H=0-1000
m |
1.00
|
0.96
|
0.92
|
0.86
|
| H=1000-2000
m |
0,96
|
0,92
|
0,86
|
0,79
|
| H=2000-3000
m |
0,92
|
0,86
|
0,79
|
0,72
|
| H=3000-4000
m |
0,86
|
0,79
|
0,72
|
0,64
|
Improving
coefficient due to the altitude and temperature is 0,86(Table 2)
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TABLO
3 Power reduction with cos phi
|
|
Cos
phi
|
1-
0.8
|
0.7
|
0.6
|
0.5
|
0.4
|
0
|
|
P/Pn
|
1.00
|
0.95
|
0.88
|
0.84
|
0.80
|
0.72
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and
improving coefficent due to the power factor is 0,95 (Table 3)
Alternator
power which will be selected (Ns) :
Ns=Power
Required / (0,86*0,95)=50 / (0,86*0,95)=61,3 KVA
Appropriate
power value 63 kVA available is selected.
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