Diesel Gen-set Operation Instructions
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6. Drying of alternator
6.1 Cold-state operation
If a normal alternator is left out of operation for a long period of time in a dusty and
moisture environment, simply operate the Gen-set with connecting wire (F1 and F2
connecting wire of AS440 and AS480, F+ and F- connecting wire of SE350) of
excitation stator (magnetic field) of AVR is disconnected for 10 minutes or longer.
Just by this, the requirement to dry winding surface and increase insulation resistance
value to 1 M
Ω
or higher so as that the Gen-set can be used for normal operation
directly can be met.
6.2 Drying by introducing air
Remove all cover plates on alternator, in order that moist air can run away. During the
process of drying, air stream shall be able to freely flows in the alternator and bring
away moisture.
Please introduce hot air into alternator from its air intake with two 1~3kW electric
hair dryers. Pay attention that winding shall be kept at least 300mm away from heat
source, in order to avoid damage of insulation caused by overheating.
Heat continuously and record insulation resistance value once every half hour. The
drying process will be completed when the resistance reaches to the valued specified
in “typical drying curve”.
Start the Gen-set again for commissioning after removing these heaters and
reinstalling all cover plates.
If the Gen-set does not operate immediately, make sure that condensation removing
heater installed on alternator is energized and operates normally. Measuring of
insulation resistance is still necessary before starting of operation next time.
6.3 Short connection method
Note: this process must be carried out by a qualified engineer who is familiar
