A machine and electrical power system includes a generator having a speed range that includes a resonance speed associated with resonance vibrations of the system. A drive coupling is disposed between the generator and an engine configured to rotate the generator and is further configured to transmit torque from the engine to the generator, the drive coupling being configured to allow relative slip between first and second elements when the generator is rotated at its resonance speed. A machine operation method includes rotating a generator with an engine, and generating resonance vibrations of at least one of the engine and the generator by rotating the generator at a resonance speed. The method further includes inhibiting transmitting resonance vibrations between the generator and the engine by allowing relative rotational slip within a drive coupling disposed between the engine and the generator.