What is the generator usually driven by?

The generator is typically driven by a belt, which connects it to an engine or another prime mover. This setup allows the engine to provide the necessary mechanical energy to spin the generator’s rotor, thus producing electricity.

Belt-driven systems are advantageous in many applications because they easily transmit power from an engine or motor to the generator. This configuration can also allow for adjustments in speed and torque, making it flexible in terms of operational requirements. In automotive contexts, for example, the alternator (a type of generator) is commonly driven by a belt connected to the engine's crankshaft.

Other options like a crankshaft, electric motor, or starter motor are not typically used for direct generator propulsion. The crankshaft might be involved in a broader context where it provides motion in an internal combustion engine, while electric motors would usually require an external power source rather than driving the generator itself. Starter motors, on the other hand, are used to initiate the engine’s operation rather than to drive the generator once the engine is running. Thus, the belt-driven approach is the most practical and common method for driving generators.