Appendix C Generator Set Output Ratings Procedure - Kohler 6EKOD Installation Manual

Appendix C Generator Set Output Ratings Procedure

Kohler Co. develops the kilowatt output rating of a Kohlerr
marine generator set based upon the calculations
specified in ISO 3046 and ISO 8528-1. The calculations
correct for environmental variables encountered in a
Generator Output
Output power is expected to be within ±5% of the specified rating when corrected to reference conditions.
Correction factors are determined using the following formulas:
1. For naturally aspirated compression-ignition engines (power limited by excess air):
C.F. = [1.175 (29.2 / Dry Barometer in. Hg)
x Alternator Efficiency
2. For turbocharged compression ignition engines:
C.F. = [1.175 (29.2 / Barometer
x Alternator Efficiency
3. For turbocharged and intercooled compression ignition engines:
C.F. = [1.175 (29.2 / Barometer
x Alternator Efficiency
Reference conditions:
Temperature: 77_F; Pressure: 29.2 in. Hg dry barometer.
Kohler sound shield increases ambient intake air approx. 12_F
Approximate derates:
Temperature: approximately 1% per 10_F (turbocharged engines have a greater derate);
Pressure (altitude): approximately 4% per 1000 ft. (1 in. Hg)
Figure 1 Generator Output
KEY
60 Hz
8.0
7.9
50 Hz
7.8
7.7
7.6
7.5
7.4
7.3
7.2
7.1
7.0
6.9
6.8
6.7
6.6
6.5
6.4
6.3
6.2
6.1
6.0
5.9
5.8
5.7
5.6
5.5
75
Figure 2 Example: 6.5EFOZ/8EOZ kW Derates (ISO 3046/ISO 8258-1)
54 Appendix
= Generator Output
corrected
/ Alternator Efficiency
Reference
Observed
/ Alternator Efficiency
Reference
Observed
/ Alternator Efficiency
Reference
80 85 90
77
generator set installation.
calculations. Figure 2 contains examples of how heat
variables affect generator set ratings.
x Correction Factor
observed
(Temperature _F + 460/537)
1
Observed
(Temperature _F + 460/537)
.7
in. Hg)
Observed
(Temperature _F + 460/537)
.7
in. Hg)
Observed
95 100 105
Temperature (_F)
Figure 1 outlines the
.75
-- .175]
2
-- .175]
1.2
-- .175]
110 115 120
TP-6773 5/12a