Large capacity generators are invariably

The correct answer is: A. water cooled

Large capacity generators are invariably water cooled. This is because water is an excellent conductor of heat, and it can be circulated through the generator to remove heat from the windings and other components. This helps to prevent the generator from overheating, which can damage the components and lead to a loss of power.

Natural air cooling is not suitable for large capacity generators because it would not be able to remove enough heat from the generator. Forced air cooling is a possibility, but it is not as efficient as water cooling. Hydrogen cooling is also a possibility, but it is more expensive than water cooling.

Here is a brief explanation of each option:

• Water cooled: Water is an excellent conductor of heat, and it can be circulated through the generator to remove heat from the windings and other components. This helps to prevent the generator from overheating, which can damage the components and lead to a loss of power.
• Natural air cooled: Natural air cooling relies on the natural flow of air to remove heat from the generator. This is not suitable for large capacity generators because it would not be able to remove enough heat from the generator.
• Forced air cooled: Forced air cooling uses fans to circulate air over the generator to remove heat. This is more efficient than natural air cooling, but it is not as efficient as water cooling.
• Hydrogen cooled: Hydrogen is a very good conductor of heat, and it can be used to cool generators. However, hydrogen is more expensive than water, and it is also more flammable.