- 17
MPL 206 A - MPL 226 A
GB
GB
2.5
D
ERATING
FOR
OPERATIVE
AMBIENT
CONDITIONS
Diesel engines
Important: the outputs of Diesel engines for stationary
applications refer to the following standard ambient
conditions in agreement with ISO 3046/1 Standard
- ambient tempe25 °C
- ambient pressure 1000 mbar (750 mm/Hg,
corresponding to 0 m. above sea level);
- relative humidity 30%.
Synchronous generators
The ambient conditions for reference for synchronous
generators and stationary applications, in agreement
with IEC 34 standards, are the following:
- ambient temperature 40 °C
- altitude 1000 metres above sea level (674 mm/Hg).
For installation and operating ambient conditions other
than those indicated for reference, appropriate “derating”
of the power supplied by the unit must be performed.
The impact of every factor described in this section must
not be considered individually but in combination with
the other factors.
The derating of synchronous generators is less
demanding than for Diesel engines; inasmuch, the
derating of the power generator in general coincides with
the derating of the Diesel engine.
Particular deratings may be determined on the basis of
the effective conditions of use.
For information: the following Table indicates the derating
values for aspirated and turbocompressed engines.
Table with derating estimates for aspirated and turbocompressed Diesel engines
(for more information about the type of intake, see “Table. Technical Features” Chap.2.4)
The two coefficients K1 and K2 must both be multiplied to the rated power of the generator to obtain the power at
ambient conditions different to standard conditions.
Resultant power = Rated power x K
1
x K
2
EXAMPLE: Machine Operation - power: 100 kVA a 35°C a 1000 m.s.l.
100 x 0.96 x 0.92 = 88.3 kVA
Altitude (m.a.s.l.) a 25°C
0
500
1000 1500 2000 2500 3000
Reduction factor (K
1
)
for naturally aspirated engine
1
0,95
0,89
0,83
0,76
0,74
0,68
Reduction factor (K
1
)
for turbo aspirated engine
1
0,96
0,92
0,88
0,83
0,79
0,75
Ambient temp. (°C) a 0 m.a.s.l.
25°
30°
35°
40°
45°
50°
Reduction factor (K
2
)
for naturally aspirated engine
1
0,98
0,96
0,95
0,93
0,91
Reduction factor (K
2
)
for turbo aspirated engine
1
0,98
0,96
0,94
0,92
0,90
