Do magnets in generators wear out?

Permanent magnets and iron rotor cores used in standard portable generators do not simply wear out or lose their magnetic charge under normal operating conditions. However, a generator can temporarily lose its residual magnetism—a phenomenon where the iron core loses the faint magnetic field required to excite the alternator windings upon startup—due to prolonged storage without use, excessive vibration, or a nearby lightning strike. When this happens, the generator engine runs fine but produces zero electricity until the field is re-magnetized. You can troubleshoot alternator magnetism safety safely by shutting off the engine completely before handling internal components. You can verify that your corrective action is successful when flashing the field windings with an external 12-volt battery restores residual magnetism and immediately brings back stable AC voltage output at the receptacles.