Final answer:
The paralleling relay points on a twin engine 12V generator system will close when the generators have equalized and stabilized voltages, allowing them to share the load. This process is related to the principles of electromagnetic induction at work in electrical generators.
Step-by-step explanation:
In a twin engine 12V generator system, paralleling relay points will typically close when the voltage levels of the generators are equalized and stable, ensuring that both generators can share the load effectively. This scenario usually occurs after one generator has been started and has stabilized, at which point the second generator is brought online. When the second generator reaches the correct speed and voltage, the relay points close, connecting the generators in parallel. The purpose is to combine the current output capacity while maintaining a constant voltage of 12V, similar to how two 12-V batteries in parallel in some diesel trucks produce a total electromotive force (emf) of 12V but can deliver a larger current necessary to start an engine.
Aspects of electromagnetic induction, such as how emf is induced in a coil when rotated in a magnetic field, play a fundamental role in understanding how generators function. According to the provided figures and information, the induced emf in a coil is at its maximum when the magnetic flux changes from its maximum to zero, which occurs when the generator's coil is rotated through one-fourth of a revolution.