Question 580Electricity & Electronics - Assistant Engineer

70% to pass

How can the loss of residual magnetism in an alternator or generator be corrected?

Aallowing the generator to run at 10% of normal speed for 5 minutes
Brunning the rotor in the opposite direction for 5 minutes
Cusing a storage battery or battery charger to 'flash' the field
Drunning the generator at normal speed with the field rheostat fully counter-clockwise
AI Explanation

The correct answer is C) using a storage battery or battery charger to 'flash' the field. This is the correct answer because applying a brief pulse of current to the field winding of an alternator or generator can help restore the residual magnetism that has been lost. The 'flashing' process magnetizes the field and reestablishes the necessary magnetic field for proper generator operation. The other options are incorrect because they do not provide the specific 'flashing' process required to restore the residual magnetism. Running the generator at reduced speed or in reverse direction, or with the field rheostat adjusted, will not effectively remagnetize the field to correct the loss of residual magnetism.

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Official Resources
46 CFR Electrical Engineering 46 CFR Machinery & Electrical USCG National Maritime Center
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