Start-up
A stand-by generator reaches nominal speed in 50-70 seconds after the start signal (check of pilot fuel in-
jection is always performed during a normal start).
With black-out start active nominal speed is reached in about 25 s (pilot fuel injection disabled).
The engine can be started with gas mode selected. It will then start using gas fuel as soon as the pilot
check is completed and the gas supply system is ready.
Start and stop on heavy fuel is not restricted.
2.3
Operation at low load and idling
Absolute idling (declutched main engine, disconnected generator):
•
Maximum 10 minutes if the engine is to be stopped after the idling. 3-5 minutes idling before stop is
recommended.
•
Maximum 6 hours if the engine is to be loaded after the idling.
Operation below 20 % load on HFO or below 10 % load on MDF or gas
•
Maximum 100 hours continuous operation. At intervals of 100 operating hours the engine must be
loaded to minimum 70 % of the rated output.
Operation above 20 % load on HFO or above 10 % load on MDF or gas
•
No restrictions.
2.4
Low air temperature
In cold conditions the following minimum inlet air temperatures apply:
Gas mode:
•
Low load + 5ºC
•
High load -10ºC
Diesel mode:
•
St 5ºC
•
Idling - 5ºC
•
High load - 10ºC
The two-stage charge air cooler is useful for heating of the charge air during prolonged low load operation
in cold conditions. Sustained operation between 0 and 40% load can however require special provisions
in cold conditions to prevent too low HT-water temperature. If necessary, the preheating arrangement can
be designed to heat the running engine (capacity to be checked).
For further guidelines, see chapter Combustion air system design.
12
Product Guide Wärtsilä 34DF - 3/2012
Product Guide
2. Operating Ranges
