When synchronizing an electrical generator and the synchronizing lamps are dark, what should be ensured about the voltage ratings?

When synchronizing an electrical generator, if the synchronizing lamps are dark, this indicates that the voltages between the generator and the line are not in alignment. For successful synchronization, the voltage of the generator must be higher than the line system voltage. This condition ensures that when the circuit breaker is closed, the generator is capable of supplying power to the system rather than being overloaded by it.

Having a voltage rating that is higher than the line system allows for proper synchronization and prevents issues such as voltage collapse or system instability that can occur if the generator voltage is too low. Moreover, ensuring the generator voltage is appropriately higher facilitates the proper flow of current into the line system upon synchronization, rather than causing a backflow that might damage the generator or the system.

In contrast, matching or having lower voltages can result in the inability to synchronize properly, ineffective power transfer, and potential operational failures.