Flashing is sometime required only in Static Excited compound generators. These type generators, the residual magnetism left over with the exciter field pole material initialising the building up of voltage while starting. If the generator not used for a long time or during the major repair/maintenance of alternator, heating the field winding to improve insulation resistancemay also result in losing these residual magnetism.
In such situation, magnetising the field poles by giving external DC (12V) is required and the same is called flashing of generators. Remove the wires F+ and F- from AVR terminals and connect a 12 volt battery to the stationary exciter field by observing the polarity. Keep connected for about 10 minutes. After 10 minutes, disconnect the battery and connect back the AVR leads. Start the engine and monitor the voltage building up in the generator. If not, repeat the same procedure again until voltage starts building up.
During flashing, it is important to disconnect the leads from AVR to protect its’ components from damage by the battery voltage which is appearing in the AVR outputs since the flashing battery also coming in parallel.
In such situation, magnetising the field poles by giving external DC (12V) is required and the same is called flashing of generators. Remove the wires F+ and F- from AVR terminals and connect a 12 volt battery to the stationary exciter field by observing the polarity. Keep connected for about 10 minutes. After 10 minutes, disconnect the battery and connect back the AVR leads. Start the engine and monitor the voltage building up in the generator. If not, repeat the same procedure again until voltage starts building up.
During flashing, it is important to disconnect the leads from AVR to protect its’ components from damage by the battery voltage which is appearing in the AVR outputs since the flashing battery also coming in parallel.
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